theorem Th29: :: SYMSP_1:29

for F being Field
for S being SymSp of F
for a, p, q, x being Element of S st (1_ F) + (1_ F) <> 0. F & not a _|_ & not x _|_ & not a _|_ & not x _|_ holds
(ProJ (a,q,p)) * (ProJ (p,a,x)) = (ProJ (x,q,p)) * (ProJ (q,a,x))