theorem Th26: :: GOBRD11:26

for j being Nat
for G being empty-yielding X_equal-in-line Y_equal-in-column Matrix of (TOP-REAL 2) st 1 <= j & j < width G holds
cell (G,0,j) = { |[r,s]| where r, s is Real : ( r <= (G * (1,1)) `1 & (G * (1,j)) `2 <= s & s <= (G * (1,(j + 1))) `2 ) }