let G be V9() Matrix of (TOP-REAL 2); :: thesis: ( G is X_equal-in-line implies v_strip (G,0) = { |[r,s]| where r, s is Real : r <= (G * (1,1)) `1 } )

0 <> width G by MATRIX_0:def 10;

then A1: 1 <= width G by NAT_1:14;

assume G is X_equal-in-line ; :: thesis: v_strip (G,0) = { |[r,s]| where r, s is Real : r <= (G * (1,1)) `1 }

hence v_strip (G,0) = { |[r,s]| where r, s is Real : r <= (G * (1,1)) `1 } by A1, GOBOARD5:10; :: thesis: verum

0 <> width G by MATRIX_0:def 10;

then A1: 1 <= width G by NAT_1:14;

assume G is X_equal-in-line ; :: thesis: v_strip (G,0) = { |[r,s]| where r, s is Real : r <= (G * (1,1)) `1 }

hence v_strip (G,0) = { |[r,s]| where r, s is Real : r <= (G * (1,1)) `1 } by A1, GOBOARD5:10; :: thesis: verum