let S be OrderSortedSign; for o1, o2 being OperSymbol of S
for A being OSAlgebra of S st o1 <= o2 holds
( Args o1,A c= Args o2,A & Result o1,A c= Result o2,A )
let o1, o2 be OperSymbol of S; for A being OSAlgebra of S st o1 <= o2 holds
( Args o1,A c= Args o2,A & Result o1,A c= Result o2,A )
let A be OSAlgebra of S; ( o1 <= o2 implies ( Args o1,A c= Args o2,A & Result o1,A c= Result o2,A ) )
assume
o1 <= o2
; ( Args o1,A c= Args o2,A & Result o1,A c= Result o2,A )
then
( the_arity_of o1 <= the_arity_of o2 & the_result_sort_of o1 <= the_result_sort_of o2 )
by Def22;
hence
( Args o1,A c= Args o2,A & Result o1,A c= Result o2,A )
by Th24, Th25; verum