theorem Th27: :: GOBRD11:27

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