:: deftheorem defines left_transitive DIRORT:def 6 :
for IT being Oriented_Orthogonality_Space holds
( IT is left_transitive iff for u, u1, u2, v, v1, v2, w, w1 being Element of IT st u,u1 '//' v,v1 & v,v1 '//' w,w1 & u,u1 '//' u2,v2 & not u = u1 & not v = v1 holds
u2,v2 '//' w,w1 );