let it1, it2 be ManySortedSet of ; :: thesis: ( ( for x being Vertex of IIG st x in dom it1 holds
it1 . x in Constants SCS,x ) & ( for x being Vertex of IIG st x in dom it2 holds
it2 . x in Constants SCS,x ) implies it1 = it2 )

assume A9: for x being Vertex of IIG st x in dom it1 holds
it1 . x in Constants SCS,x ; :: thesis: ( ex x being Vertex of IIG st
( x in dom it2 & not it2 . x in Constants SCS,x ) or it1 = it2 )

assume A10: for x being Vertex of IIG st x in dom it2 holds
it2 . x in Constants SCS,x ; :: thesis: it1 = it2
now
let i be set ; :: thesis: ( i in SortsWithConstants IIG implies it1 . i = it2 . i )
assume A11: i in SortsWithConstants IIG ; :: thesis: it1 . i = it2 . i
then reconsider v = i as Vertex of IIG ;
( dom it1 = SortsWithConstants IIG & dom it2 = SortsWithConstants IIG ) by PARTFUN1:def 4;
then A12: ( it1 . v in Constants SCS,v & it2 . v in Constants SCS,v ) by A9, A10, A11;
consider A being non empty set such that
A13: ( A = the Sorts of SCS . v & Constants SCS,v = { a where a is Element of A : ex o being OperSymbol of IIG st
( the Arity of IIG . o = {} & the ResultSort of IIG . o = v & a in rng (Den o,SCS) )
}
) by MSUALG_2:def 4;
consider a1 being Element of the Sorts of SCS . v such that
A14: it1 . v = a1 and
A15: ex o being OperSymbol of IIG st
( the Arity of IIG . o = {} & the ResultSort of IIG . o = v & a1 in rng (Den o,SCS) ) by A12, A13;
consider a2 being Element of the Sorts of SCS . v such that
A16: it2 . v = a2 and
A17: ex o being OperSymbol of IIG st
( the Arity of IIG . o = {} & the ResultSort of IIG . o = v & a2 in rng (Den o,SCS) ) by A12, A13;
consider o1 being OperSymbol of IIG such that
A18: the Arity of IIG . o1 = {} and
A19: the ResultSort of IIG . o1 = v and
A20: a1 in rng (Den o1,SCS) by A15;
consider o2 being OperSymbol of IIG such that
the Arity of IIG . o2 = {} and
A21: the ResultSort of IIG . o2 = v and
A22: a2 in rng (Den o2,SCS) by A17;
A23: ( the_result_sort_of o1 = v & the_result_sort_of o2 = v ) by A19, A21, MSUALG_1:def 7;
then A24: o1 = o2 by MSAFREE2:def 6;
A25: dom the Arity of IIG = the carrier' of IIG by FUNCT_2:def 1;
A26: {} = <*> the carrier of IIG ;
A27: dom (Den o1,SCS) = Args o1,SCS by FUNCT_2:def 1
.= ((the Sorts of SCS # ) * the Arity of IIG) . o1 by MSUALG_1:def 9
.= (the Sorts of SCS # ) . (the Arity of IIG . o1) by A25, FUNCT_1:23
.= {{} } by A18, A26, PRE_CIRC:5 ;
consider x1 being set such that
A28: x1 in dom (Den o1,SCS) and
A29: a1 = (Den o1,SCS) . x1 by A20, FUNCT_1:def 5;
consider x2 being set such that
A30: x2 in dom (Den o2,SCS) and
A31: a2 = (Den o2,SCS) . x2 by A22, FUNCT_1:def 5;
( x1 = {} & x2 = {} ) by A24, A27, A28, A30, TARSKI:def 1;
hence it1 . i = it2 . i by A14, A16, A23, A29, A31, MSAFREE2:def 6; :: thesis: verum
end;
hence it1 = it2 by PBOOLE:3; :: thesis: verum