let s0, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13, s14, s15, ns0, ns1, ns2, ns3, ns4, ns5, ns6, ns7, ns8, ns9, ns10, ns11, ns12, ns13, ns14, ns15, q1, q2, q3, q4, nq1, nq2, nq3, nq4 be set ; :: thesis: not ( ( not s0 is empty implies not AND4 ((NOT1 q4),(NOT1 q3),(NOT1 q2),(NOT1 q1)) is empty ) & ( not AND4 ((NOT1 q4),(NOT1 q3),(NOT1 q2),(NOT1 q1)) is empty implies not s0 is empty ) & ( not s1 is empty implies not AND4 ((NOT1 q4),(NOT1 q3),(NOT1 q2),q1) is empty ) & ( not AND4 ((NOT1 q4),(NOT1 q3),(NOT1 q2),q1) is empty implies not s1 is empty ) & ( not s2 is empty implies not AND4 ((NOT1 q4),(NOT1 q3),q2,(NOT1 q1)) is empty ) & ( not AND4 ((NOT1 q4),(NOT1 q3),q2,(NOT1 q1)) is empty implies not s2 is empty ) & ( not s3 is empty implies not AND4 ((NOT1 q4),(NOT1 q3),q2,q1) is empty ) & ( not AND4 ((NOT1 q4),(NOT1 q3),q2,q1) is empty implies not s3 is empty ) & ( not s4 is empty implies not AND4 ((NOT1 q4),q3,(NOT1 q2),(NOT1 q1)) is empty ) & ( not AND4 ((NOT1 q4),q3,(NOT1 q2),(NOT1 q1)) is empty implies not s4 is empty ) & ( not s5 is empty implies not AND4 ((NOT1 q4),q3,(NOT1 q2),q1) is empty ) & ( not AND4 ((NOT1 q4),q3,(NOT1 q2),q1) is empty implies not s5 is empty ) & ( not s6 is empty implies not AND4 ((NOT1 q4),q3,q2,(NOT1 q1)) is empty ) & ( not AND4 ((NOT1 q4),q3,q2,(NOT1 q1)) is empty implies not s6 is empty ) & ( not s7 is empty implies not AND4 ((NOT1 q4),q3,q2,q1) is empty ) & ( not AND4 ((NOT1 q4),q3,q2,q1) is empty implies not s7 is empty ) & ( not s8 is empty implies not AND4 (q4,(NOT1 q3),(NOT1 q2),(NOT1 q1)) is empty ) & ( not AND4 (q4,(NOT1 q3),(NOT1 q2),(NOT1 q1)) is empty implies not s8 is empty ) & ( not s9 is empty implies not AND4 (q4,(NOT1 q3),(NOT1 q2),q1) is empty ) & ( not AND4 (q4,(NOT1 q3),(NOT1 q2),q1) is empty implies not s9 is empty ) & ( not s10 is empty implies not AND4 (q4,(NOT1 q3),q2,(NOT1 q1)) is empty ) & ( not AND4 (q4,(NOT1 q3),q2,(NOT1 q1)) is empty implies not s10 is empty ) & ( not s11 is empty implies not AND4 (q4,(NOT1 q3),q2,q1) is empty ) & ( not AND4 (q4,(NOT1 q3),q2,q1) is empty implies not s11 is empty ) & ( not s12 is empty implies not AND4 (q4,q3,(NOT1 q2),(NOT1 q1)) is empty ) & ( not AND4 (q4,q3,(NOT1 q2),(NOT1 q1)) is empty implies not s12 is empty ) & ( not s13 is empty implies not AND4 (q4,q3,(NOT1 q2),q1) is empty ) & ( not AND4 (q4,q3,(NOT1 q2),q1) is empty implies not s13 is empty ) & ( not s14 is empty implies not AND4 (q4,q3,q2,(NOT1 q1)) is empty ) & ( not AND4 (q4,q3,q2,(NOT1 q1)) is empty implies not s14 is empty ) & ( not s15 is empty implies not AND4 (q4,q3,q2,q1) is empty ) & ( not AND4 (q4,q3,q2,q1) is empty implies not s15 is empty ) & ( not ns0 is empty implies not AND4 ((NOT1 nq4),(NOT1 nq3),(NOT1 nq2),(NOT1 nq1)) is empty ) & ( not AND4 ((NOT1 nq4),(NOT1 nq3),(NOT1 nq2),(NOT1 nq1)) is empty implies not ns0 is empty ) & ( not ns1 is empty implies not AND4 ((NOT1 nq4),(NOT1 nq3),(NOT1 nq2),nq1) is empty ) & ( not AND4 ((NOT1 nq4),(NOT1 nq3),(NOT1 nq2),nq1) is empty implies not ns1 is empty ) & ( not ns2 is empty implies not AND4 ((NOT1 nq4),(NOT1 nq3),nq2,(NOT1 nq1)) is empty ) & ( not AND4 ((NOT1 nq4),(NOT1 nq3),nq2,(NOT1 nq1)) is empty implies not ns2 is empty ) & ( not ns3 is empty implies not AND4 ((NOT1 nq4),(NOT1 nq3),nq2,nq1) is empty ) & ( not AND4 ((NOT1 nq4),(NOT1 nq3),nq2,nq1) is empty implies not ns3 is empty ) & ( not ns4 is empty implies not AND4 ((NOT1 nq4),nq3,(NOT1 nq2),(NOT1 nq1)) is empty ) & ( not AND4 ((NOT1 nq4),nq3,(NOT1 nq2),(NOT1 nq1)) is empty implies not ns4 is empty ) & ( not ns5 is empty implies not AND4 ((NOT1 nq4),nq3,(NOT1 nq2),nq1) is empty ) & ( not AND4 ((NOT1 nq4),nq3,(NOT1 nq2),nq1) is empty implies not ns5 is empty ) & ( not ns6 is empty implies not AND4 ((NOT1 nq4),nq3,nq2,(NOT1 nq1)) is empty ) & ( not AND4 ((NOT1 nq4),nq3,nq2,(NOT1 nq1)) is empty implies not ns6 is empty ) & ( not ns7 is empty implies not AND4 ((NOT1 nq4),nq3,nq2,nq1) is empty ) & ( not AND4 ((NOT1 nq4),nq3,nq2,nq1) is empty implies not ns7 is empty ) & ( not ns8 is empty implies not AND4 (nq4,(NOT1 nq3),(NOT1 nq2),(NOT1 nq1)) is empty ) & ( not AND4 (nq4,(NOT1 nq3),(NOT1 nq2),(NOT1 nq1)) is empty implies not ns8 is empty ) & ( not ns9 is empty implies not AND4 (nq4,(NOT1 nq3),(NOT1 nq2),nq1) is empty ) & ( not AND4 (nq4,(NOT1 nq3),(NOT1 nq2),nq1) is empty implies not ns9 is empty ) & ( not ns10 is empty implies not AND4 (nq4,(NOT1 nq3),nq2,(NOT1 nq1)) is empty ) & ( not AND4 (nq4,(NOT1 nq3),nq2,(NOT1 nq1)) is empty implies not ns10 is empty ) & ( not ns11 is empty implies not AND4 (nq4,(NOT1 nq3),nq2,nq1) is empty ) & ( not AND4 (nq4,(NOT1 nq3),nq2,nq1) is empty implies not ns11 is empty ) & ( not ns12 is empty implies not AND4 (nq4,nq3,(NOT1 nq2),(NOT1 nq1)) is empty ) & ( not AND4 (nq4,nq3,(NOT1 nq2),(NOT1 nq1)) is empty implies not ns12 is empty ) & ( not ns13 is empty implies not AND4 (nq4,nq3,(NOT1 nq2),nq1) is empty ) & ( not AND4 (nq4,nq3,(NOT1 nq2),nq1) is empty implies not ns13 is empty ) & ( not ns14 is empty implies not AND4 (nq4,nq3,nq2,(NOT1 nq1)) is empty ) & ( not AND4 (nq4,nq3,nq2,(NOT1 nq1)) is empty implies not ns14 is empty ) & ( not ns15 is empty implies not AND4 (nq4,nq3,nq2,nq1) is empty ) & ( not AND4 (nq4,nq3,nq2,nq1) is empty implies not ns15 is empty ) & ( not nq1 is empty implies not NOT1 q4 is empty ) & ( not NOT1 q4 is empty implies not nq1 is empty ) & ( not nq2 is empty implies not q1 is empty ) & ( not q1 is empty implies not nq2 is empty ) & ( not nq3 is empty implies not q2 is empty ) & ( not q2 is empty implies not nq3 is empty ) & ( not nq4 is empty implies not q3 is empty ) & ( not q3 is empty implies not nq4 is empty ) & not ( ( not ns1 is empty implies not s0 is empty ) & ( not s0 is empty implies not ns1 is empty ) & ( not ns3 is empty implies not s1 is empty ) & ( not s1 is empty implies not ns3 is empty ) & ( not ns7 is empty implies not s3 is empty ) & ( not s3 is empty implies not ns7 is empty ) & ( not ns15 is empty implies not s7 is empty ) & ( not s7 is empty implies not ns15 is empty ) & ( not ns14 is empty implies not s15 is empty ) & ( not s15 is empty implies not ns14 is empty ) & ( not ns12 is empty implies not s14 is empty ) & ( not s14 is empty implies not ns12 is empty ) & ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) ) )

assume that

A1: ( not s0 is empty iff not AND4 ((NOT1 q4),(NOT1 q3),(NOT1 q2),(NOT1 q1)) is empty ) and

A2: ( not s1 is empty iff not AND4 ((NOT1 q4),(NOT1 q3),(NOT1 q2),q1) is empty ) and

A3: ( not s2 is empty iff not AND4 ((NOT1 q4),(NOT1 q3),q2,(NOT1 q1)) is empty ) and

A4: ( not s3 is empty iff not AND4 ((NOT1 q4),(NOT1 q3),q2,q1) is empty ) and

A5: ( not s4 is empty iff not AND4 ((NOT1 q4),q3,(NOT1 q2),(NOT1 q1)) is empty ) and

A6: ( not s5 is empty iff not AND4 ((NOT1 q4),q3,(NOT1 q2),q1) is empty ) and

A7: ( not s6 is empty iff not AND4 ((NOT1 q4),q3,q2,(NOT1 q1)) is empty ) and

A8: ( not s7 is empty iff not AND4 ((NOT1 q4),q3,q2,q1) is empty ) and

A9: ( not s8 is empty iff not AND4 (q4,(NOT1 q3),(NOT1 q2),(NOT1 q1)) is empty ) and

A10: ( not s9 is empty iff not AND4 (q4,(NOT1 q3),(NOT1 q2),q1) is empty ) and

A11: ( not s10 is empty iff not AND4 (q4,(NOT1 q3),q2,(NOT1 q1)) is empty ) and

A12: ( not s11 is empty iff not AND4 (q4,(NOT1 q3),q2,q1) is empty ) and

A13: ( not s12 is empty iff not AND4 (q4,q3,(NOT1 q2),(NOT1 q1)) is empty ) and

A14: ( not s13 is empty iff not AND4 (q4,q3,(NOT1 q2),q1) is empty ) and

A15: ( not s14 is empty iff not AND4 (q4,q3,q2,(NOT1 q1)) is empty ) and

A16: ( not s15 is empty iff not AND4 (q4,q3,q2,q1) is empty ) and

A17: ( not ns0 is empty iff not AND4 ((NOT1 nq4),(NOT1 nq3),(NOT1 nq2),(NOT1 nq1)) is empty ) and

A18: ( not ns1 is empty iff not AND4 ((NOT1 nq4),(NOT1 nq3),(NOT1 nq2),nq1) is empty ) and

A19: ( not ns2 is empty iff not AND4 ((NOT1 nq4),(NOT1 nq3),nq2,(NOT1 nq1)) is empty ) and

A20: ( not ns3 is empty iff not AND4 ((NOT1 nq4),(NOT1 nq3),nq2,nq1) is empty ) and

A21: ( not ns4 is empty iff not AND4 ((NOT1 nq4),nq3,(NOT1 nq2),(NOT1 nq1)) is empty ) and

A22: ( not ns5 is empty iff not AND4 ((NOT1 nq4),nq3,(NOT1 nq2),nq1) is empty ) and

A23: ( not ns6 is empty iff not AND4 ((NOT1 nq4),nq3,nq2,(NOT1 nq1)) is empty ) and

A24: ( not ns7 is empty iff not AND4 ((NOT1 nq4),nq3,nq2,nq1) is empty ) and

A25: ( not ns8 is empty iff not AND4 (nq4,(NOT1 nq3),(NOT1 nq2),(NOT1 nq1)) is empty ) and

A26: ( not ns9 is empty iff not AND4 (nq4,(NOT1 nq3),(NOT1 nq2),nq1) is empty ) and

A27: ( not ns10 is empty iff not AND4 (nq4,(NOT1 nq3),nq2,(NOT1 nq1)) is empty ) and

A28: ( not ns11 is empty iff not AND4 (nq4,(NOT1 nq3),nq2,nq1) is empty ) and

A29: ( not ns12 is empty iff not AND4 (nq4,nq3,(NOT1 nq2),(NOT1 nq1)) is empty ) and

A30: ( not ns13 is empty iff not AND4 (nq4,nq3,(NOT1 nq2),nq1) is empty ) and

A31: ( not ns14 is empty iff not AND4 (nq4,nq3,nq2,(NOT1 nq1)) is empty ) and

A32: ( not ns15 is empty iff not AND4 (nq4,nq3,nq2,nq1) is empty ) and

A33: ( ( not nq1 is empty implies not NOT1 q4 is empty ) & ( not NOT1 q4 is empty implies not nq1 is empty ) & ( not nq2 is empty implies not q1 is empty ) & ( not q1 is empty implies not nq2 is empty ) & ( not nq3 is empty implies not q2 is empty ) & ( not q2 is empty implies not nq3 is empty ) & ( not nq4 is empty implies not q3 is empty ) & ( not q3 is empty implies not nq4 is empty ) ) ; :: thesis: ( ( not ns1 is empty implies not s0 is empty ) & ( not s0 is empty implies not ns1 is empty ) & ( not ns3 is empty implies not s1 is empty ) & ( not s1 is empty implies not ns3 is empty ) & ( not ns7 is empty implies not s3 is empty ) & ( not s3 is empty implies not ns7 is empty ) & ( not ns15 is empty implies not s7 is empty ) & ( not s7 is empty implies not ns15 is empty ) & ( not ns14 is empty implies not s15 is empty ) & ( not s15 is empty implies not ns14 is empty ) & ( not ns12 is empty implies not s14 is empty ) & ( not s14 is empty implies not ns12 is empty ) & ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns1 is empty iff not s0 is empty ) by A1, A18, A33, GATE_1:20; :: thesis: ( ( not ns3 is empty implies not s1 is empty ) & ( not s1 is empty implies not ns3 is empty ) & ( not ns7 is empty implies not s3 is empty ) & ( not s3 is empty implies not ns7 is empty ) & ( not ns15 is empty implies not s7 is empty ) & ( not s7 is empty implies not ns15 is empty ) & ( not ns14 is empty implies not s15 is empty ) & ( not s15 is empty implies not ns14 is empty ) & ( not ns12 is empty implies not s14 is empty ) & ( not s14 is empty implies not ns12 is empty ) & ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns3 is empty iff not s1 is empty ) by A2, A20, A33, GATE_1:20; :: thesis: ( ( not ns7 is empty implies not s3 is empty ) & ( not s3 is empty implies not ns7 is empty ) & ( not ns15 is empty implies not s7 is empty ) & ( not s7 is empty implies not ns15 is empty ) & ( not ns14 is empty implies not s15 is empty ) & ( not s15 is empty implies not ns14 is empty ) & ( not ns12 is empty implies not s14 is empty ) & ( not s14 is empty implies not ns12 is empty ) & ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns7 is empty iff not s3 is empty ) by A4, A24, A33, GATE_1:20; :: thesis: ( ( not ns15 is empty implies not s7 is empty ) & ( not s7 is empty implies not ns15 is empty ) & ( not ns14 is empty implies not s15 is empty ) & ( not s15 is empty implies not ns14 is empty ) & ( not ns12 is empty implies not s14 is empty ) & ( not s14 is empty implies not ns12 is empty ) & ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns15 is empty iff not s7 is empty ) by A8, A32, A33, GATE_1:20; :: thesis: ( ( not ns14 is empty implies not s15 is empty ) & ( not s15 is empty implies not ns14 is empty ) & ( not ns12 is empty implies not s14 is empty ) & ( not s14 is empty implies not ns12 is empty ) & ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

( not ns14 is empty iff ( not q4 is empty & not q3 is empty & not q2 is empty & not q1 is empty ) ) by A31, A33, GATE_1:20;

hence ( not ns14 is empty iff not s15 is empty ) by A16, GATE_1:20; :: thesis: ( ( not ns12 is empty implies not s14 is empty ) & ( not s14 is empty implies not ns12 is empty ) & ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

( not ns12 is empty iff ( not q4 is empty & not q3 is empty & not q2 is empty & not NOT1 q1 is empty ) ) by A29, A33, GATE_1:20;

hence ( not ns12 is empty iff not s14 is empty ) by A15, GATE_1:20; :: thesis: ( ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

( not ns8 is empty iff ( not q4 is empty & not q3 is empty & not NOT1 q2 is empty & not NOT1 q1 is empty ) ) by A25, A33, GATE_1:20;

hence ( not ns8 is empty iff not s12 is empty ) by A13, GATE_1:20; :: thesis: ( ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

( not ns0 is empty iff ( not q4 is empty & not NOT1 q3 is empty & not NOT1 q2 is empty & not NOT1 q1 is empty ) ) by A17, A33, GATE_1:20;

hence ( not ns0 is empty iff not s8 is empty ) by A9, GATE_1:20; :: thesis: ( ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns5 is empty iff not s2 is empty ) by A3, A22, A33, GATE_1:20; :: thesis: ( ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns11 is empty iff not s5 is empty ) by A6, A28, A33, GATE_1:20; :: thesis: ( ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

( not ns6 is empty iff ( not q4 is empty & not NOT1 q3 is empty & not q2 is empty & not q1 is empty ) ) by A23, A33, GATE_1:20;

hence ( not ns6 is empty iff not s11 is empty ) by A12, GATE_1:20; :: thesis: ( ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns13 is empty iff not s6 is empty ) by A7, A30, A33, GATE_1:20; :: thesis: ( ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

( not ns10 is empty iff ( not q4 is empty & not q3 is empty & not NOT1 q2 is empty & not q1 is empty ) ) by A27, A33, GATE_1:20;

hence ( not ns10 is empty iff not s13 is empty ) by A14, GATE_1:20; :: thesis: ( ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

( not ns4 is empty iff ( not q4 is empty & not NOT1 q3 is empty & not q2 is empty & not NOT1 q1 is empty ) ) by A21, A33, GATE_1:20;

hence ( not ns4 is empty iff not s10 is empty ) by A11, GATE_1:20; :: thesis: ( ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns9 is empty iff not s4 is empty ) by A5, A26, A33, GATE_1:20; :: thesis: ( not ns2 is empty iff not s9 is empty )

( not ns2 is empty iff ( not q4 is empty & not NOT1 q3 is empty & not NOT1 q2 is empty & not q1 is empty ) ) by A19, A33, GATE_1:20;

hence ( not ns2 is empty iff not s9 is empty ) by A10, GATE_1:20; :: thesis: verum

assume that

A1: ( not s0 is empty iff not AND4 ((NOT1 q4),(NOT1 q3),(NOT1 q2),(NOT1 q1)) is empty ) and

A2: ( not s1 is empty iff not AND4 ((NOT1 q4),(NOT1 q3),(NOT1 q2),q1) is empty ) and

A3: ( not s2 is empty iff not AND4 ((NOT1 q4),(NOT1 q3),q2,(NOT1 q1)) is empty ) and

A4: ( not s3 is empty iff not AND4 ((NOT1 q4),(NOT1 q3),q2,q1) is empty ) and

A5: ( not s4 is empty iff not AND4 ((NOT1 q4),q3,(NOT1 q2),(NOT1 q1)) is empty ) and

A6: ( not s5 is empty iff not AND4 ((NOT1 q4),q3,(NOT1 q2),q1) is empty ) and

A7: ( not s6 is empty iff not AND4 ((NOT1 q4),q3,q2,(NOT1 q1)) is empty ) and

A8: ( not s7 is empty iff not AND4 ((NOT1 q4),q3,q2,q1) is empty ) and

A9: ( not s8 is empty iff not AND4 (q4,(NOT1 q3),(NOT1 q2),(NOT1 q1)) is empty ) and

A10: ( not s9 is empty iff not AND4 (q4,(NOT1 q3),(NOT1 q2),q1) is empty ) and

A11: ( not s10 is empty iff not AND4 (q4,(NOT1 q3),q2,(NOT1 q1)) is empty ) and

A12: ( not s11 is empty iff not AND4 (q4,(NOT1 q3),q2,q1) is empty ) and

A13: ( not s12 is empty iff not AND4 (q4,q3,(NOT1 q2),(NOT1 q1)) is empty ) and

A14: ( not s13 is empty iff not AND4 (q4,q3,(NOT1 q2),q1) is empty ) and

A15: ( not s14 is empty iff not AND4 (q4,q3,q2,(NOT1 q1)) is empty ) and

A16: ( not s15 is empty iff not AND4 (q4,q3,q2,q1) is empty ) and

A17: ( not ns0 is empty iff not AND4 ((NOT1 nq4),(NOT1 nq3),(NOT1 nq2),(NOT1 nq1)) is empty ) and

A18: ( not ns1 is empty iff not AND4 ((NOT1 nq4),(NOT1 nq3),(NOT1 nq2),nq1) is empty ) and

A19: ( not ns2 is empty iff not AND4 ((NOT1 nq4),(NOT1 nq3),nq2,(NOT1 nq1)) is empty ) and

A20: ( not ns3 is empty iff not AND4 ((NOT1 nq4),(NOT1 nq3),nq2,nq1) is empty ) and

A21: ( not ns4 is empty iff not AND4 ((NOT1 nq4),nq3,(NOT1 nq2),(NOT1 nq1)) is empty ) and

A22: ( not ns5 is empty iff not AND4 ((NOT1 nq4),nq3,(NOT1 nq2),nq1) is empty ) and

A23: ( not ns6 is empty iff not AND4 ((NOT1 nq4),nq3,nq2,(NOT1 nq1)) is empty ) and

A24: ( not ns7 is empty iff not AND4 ((NOT1 nq4),nq3,nq2,nq1) is empty ) and

A25: ( not ns8 is empty iff not AND4 (nq4,(NOT1 nq3),(NOT1 nq2),(NOT1 nq1)) is empty ) and

A26: ( not ns9 is empty iff not AND4 (nq4,(NOT1 nq3),(NOT1 nq2),nq1) is empty ) and

A27: ( not ns10 is empty iff not AND4 (nq4,(NOT1 nq3),nq2,(NOT1 nq1)) is empty ) and

A28: ( not ns11 is empty iff not AND4 (nq4,(NOT1 nq3),nq2,nq1) is empty ) and

A29: ( not ns12 is empty iff not AND4 (nq4,nq3,(NOT1 nq2),(NOT1 nq1)) is empty ) and

A30: ( not ns13 is empty iff not AND4 (nq4,nq3,(NOT1 nq2),nq1) is empty ) and

A31: ( not ns14 is empty iff not AND4 (nq4,nq3,nq2,(NOT1 nq1)) is empty ) and

A32: ( not ns15 is empty iff not AND4 (nq4,nq3,nq2,nq1) is empty ) and

A33: ( ( not nq1 is empty implies not NOT1 q4 is empty ) & ( not NOT1 q4 is empty implies not nq1 is empty ) & ( not nq2 is empty implies not q1 is empty ) & ( not q1 is empty implies not nq2 is empty ) & ( not nq3 is empty implies not q2 is empty ) & ( not q2 is empty implies not nq3 is empty ) & ( not nq4 is empty implies not q3 is empty ) & ( not q3 is empty implies not nq4 is empty ) ) ; :: thesis: ( ( not ns1 is empty implies not s0 is empty ) & ( not s0 is empty implies not ns1 is empty ) & ( not ns3 is empty implies not s1 is empty ) & ( not s1 is empty implies not ns3 is empty ) & ( not ns7 is empty implies not s3 is empty ) & ( not s3 is empty implies not ns7 is empty ) & ( not ns15 is empty implies not s7 is empty ) & ( not s7 is empty implies not ns15 is empty ) & ( not ns14 is empty implies not s15 is empty ) & ( not s15 is empty implies not ns14 is empty ) & ( not ns12 is empty implies not s14 is empty ) & ( not s14 is empty implies not ns12 is empty ) & ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns1 is empty iff not s0 is empty ) by A1, A18, A33, GATE_1:20; :: thesis: ( ( not ns3 is empty implies not s1 is empty ) & ( not s1 is empty implies not ns3 is empty ) & ( not ns7 is empty implies not s3 is empty ) & ( not s3 is empty implies not ns7 is empty ) & ( not ns15 is empty implies not s7 is empty ) & ( not s7 is empty implies not ns15 is empty ) & ( not ns14 is empty implies not s15 is empty ) & ( not s15 is empty implies not ns14 is empty ) & ( not ns12 is empty implies not s14 is empty ) & ( not s14 is empty implies not ns12 is empty ) & ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns3 is empty iff not s1 is empty ) by A2, A20, A33, GATE_1:20; :: thesis: ( ( not ns7 is empty implies not s3 is empty ) & ( not s3 is empty implies not ns7 is empty ) & ( not ns15 is empty implies not s7 is empty ) & ( not s7 is empty implies not ns15 is empty ) & ( not ns14 is empty implies not s15 is empty ) & ( not s15 is empty implies not ns14 is empty ) & ( not ns12 is empty implies not s14 is empty ) & ( not s14 is empty implies not ns12 is empty ) & ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns7 is empty iff not s3 is empty ) by A4, A24, A33, GATE_1:20; :: thesis: ( ( not ns15 is empty implies not s7 is empty ) & ( not s7 is empty implies not ns15 is empty ) & ( not ns14 is empty implies not s15 is empty ) & ( not s15 is empty implies not ns14 is empty ) & ( not ns12 is empty implies not s14 is empty ) & ( not s14 is empty implies not ns12 is empty ) & ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns15 is empty iff not s7 is empty ) by A8, A32, A33, GATE_1:20; :: thesis: ( ( not ns14 is empty implies not s15 is empty ) & ( not s15 is empty implies not ns14 is empty ) & ( not ns12 is empty implies not s14 is empty ) & ( not s14 is empty implies not ns12 is empty ) & ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

( not ns14 is empty iff ( not q4 is empty & not q3 is empty & not q2 is empty & not q1 is empty ) ) by A31, A33, GATE_1:20;

hence ( not ns14 is empty iff not s15 is empty ) by A16, GATE_1:20; :: thesis: ( ( not ns12 is empty implies not s14 is empty ) & ( not s14 is empty implies not ns12 is empty ) & ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

( not ns12 is empty iff ( not q4 is empty & not q3 is empty & not q2 is empty & not NOT1 q1 is empty ) ) by A29, A33, GATE_1:20;

hence ( not ns12 is empty iff not s14 is empty ) by A15, GATE_1:20; :: thesis: ( ( not ns8 is empty implies not s12 is empty ) & ( not s12 is empty implies not ns8 is empty ) & ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

( not ns8 is empty iff ( not q4 is empty & not q3 is empty & not NOT1 q2 is empty & not NOT1 q1 is empty ) ) by A25, A33, GATE_1:20;

hence ( not ns8 is empty iff not s12 is empty ) by A13, GATE_1:20; :: thesis: ( ( not ns0 is empty implies not s8 is empty ) & ( not s8 is empty implies not ns0 is empty ) & ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

( not ns0 is empty iff ( not q4 is empty & not NOT1 q3 is empty & not NOT1 q2 is empty & not NOT1 q1 is empty ) ) by A17, A33, GATE_1:20;

hence ( not ns0 is empty iff not s8 is empty ) by A9, GATE_1:20; :: thesis: ( ( not ns5 is empty implies not s2 is empty ) & ( not s2 is empty implies not ns5 is empty ) & ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns5 is empty iff not s2 is empty ) by A3, A22, A33, GATE_1:20; :: thesis: ( ( not ns11 is empty implies not s5 is empty ) & ( not s5 is empty implies not ns11 is empty ) & ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns11 is empty iff not s5 is empty ) by A6, A28, A33, GATE_1:20; :: thesis: ( ( not ns6 is empty implies not s11 is empty ) & ( not s11 is empty implies not ns6 is empty ) & ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

( not ns6 is empty iff ( not q4 is empty & not NOT1 q3 is empty & not q2 is empty & not q1 is empty ) ) by A23, A33, GATE_1:20;

hence ( not ns6 is empty iff not s11 is empty ) by A12, GATE_1:20; :: thesis: ( ( not ns13 is empty implies not s6 is empty ) & ( not s6 is empty implies not ns13 is empty ) & ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns13 is empty iff not s6 is empty ) by A7, A30, A33, GATE_1:20; :: thesis: ( ( not ns10 is empty implies not s13 is empty ) & ( not s13 is empty implies not ns10 is empty ) & ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

( not ns10 is empty iff ( not q4 is empty & not q3 is empty & not NOT1 q2 is empty & not q1 is empty ) ) by A27, A33, GATE_1:20;

hence ( not ns10 is empty iff not s13 is empty ) by A14, GATE_1:20; :: thesis: ( ( not ns4 is empty implies not s10 is empty ) & ( not s10 is empty implies not ns4 is empty ) & ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

( not ns4 is empty iff ( not q4 is empty & not NOT1 q3 is empty & not q2 is empty & not NOT1 q1 is empty ) ) by A21, A33, GATE_1:20;

hence ( not ns4 is empty iff not s10 is empty ) by A11, GATE_1:20; :: thesis: ( ( not ns9 is empty implies not s4 is empty ) & ( not s4 is empty implies not ns9 is empty ) & ( not ns2 is empty implies not s9 is empty ) & ( not s9 is empty implies not ns2 is empty ) )

thus ( not ns9 is empty iff not s4 is empty ) by A5, A26, A33, GATE_1:20; :: thesis: ( not ns2 is empty iff not s9 is empty )

( not ns2 is empty iff ( not q4 is empty & not NOT1 q3 is empty & not NOT1 q2 is empty & not q1 is empty ) ) by A19, A33, GATE_1:20;

hence ( not ns2 is empty iff not s9 is empty ) by A10, GATE_1:20; :: thesis: verum