theorem Th29: :: GOBRD11:29

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,(len G),j) = { |[r,s]| where r, s is Real : ( (G * ((len G),1)) `1 <= r & (G * (1,j)) `2 <= s & s <= (G * (1,(j + 1))) `2 ) }