theorem Th20: :: PASCAL:20

for MABF, MABE, MACF, MBDF, MCDE, MACE, MBDE, MCDF being Matrix of 3,F_Real
for p1, p2, p3, p4, p5, p6 being Point of (TOP-REAL 3) st MABE = <*p1,p2,p5*> & MACF = <*p1,p3,p6*> & MBDF = <*p2,p4,p6*> & MCDE = <*p3,p4,p5*> & MABF = <*p1,p2,p6*> & MACE = <*p1,p3,p5*> & MBDE = <*p2,p4,p5*> & MCDF = <*p3,p4,p6*> holds
( Det MABE = |{p1,p2,p5}| & Det MACF = |{p1,p3,p6}| & Det MBDF = |{p2,p4,p6}| & Det MCDE = |{p3,p4,p5}| & Det MABF = |{p1,p2,p6}| & Det MACE = |{p1,p3,p5}| & Det MBDE = |{p2,p4,p5}| & Det MCDF = |{p3,p4,p6}| )