let G be empty-yielding 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