let D be non empty set ; :: thesis: for f1, f2, f3 being BinominativeFunction of D
for p, q, r, w being PartialPredicate of D st <*p,f1,q*> is SFHT of D & <*q,f2,r*> is SFHT of D & <*r,f3,w*> is SFHT of D & <*(PP_inversion q),f2,r*> is SFHT of D & <*(PP_inversion r),f3,w*> is SFHT of D holds
<*p,(PP_composition (f1,f2,f3)),w*> is SFHT of D
let f1, f2, f3 be BinominativeFunction of D; :: thesis: for p, q, r, w being PartialPredicate of D st <*p,f1,q*> is SFHT of D & <*q,f2,r*> is SFHT of D & <*r,f3,w*> is SFHT of D & <*(PP_inversion q),f2,r*> is SFHT of D & <*(PP_inversion r),f3,w*> is SFHT of D holds
<*p,(PP_composition (f1,f2,f3)),w*> is SFHT of D
let p, q, r, w be PartialPredicate of D; :: thesis: ( <*p,f1,q*> is SFHT of D & <*q,f2,r*> is SFHT of D & <*r,f3,w*> is SFHT of D & <*(PP_inversion q),f2,r*> is SFHT of D & <*(PP_inversion r),f3,w*> is SFHT of D implies <*p,(PP_composition (f1,f2,f3)),w*> is SFHT of D )
assume that
A1: <*p,f1,q*> is SFHT of D and
A2: <*q,f2,r*> is SFHT of D and
A3: <*r,f3,w*> is SFHT of D and
A4: <*(PP_inversion q),f2,r*> is SFHT of D and
A5: <*(PP_inversion r),f3,w*> is SFHT of D ; :: thesis: <*p,(PP_composition (f1,f2,f3)),w*> is SFHT of D
<*p,(PP_composition (f1,f2)),r*> is SFHT of D by A1, A2, A4, NOMIN_3:25;
hence <*p,(PP_composition (f1,f2,f3)),w*> is SFHT of D by A3, A5, NOMIN_3:25; :: thesis: verum