let U1, U2 be Universal_Algebra; :: thesis: for h being Function of U1,U2 st U1,U2 are_similar holds
for o being OperSymbol of (MSSign U1)
for y being Element of Args o,(MSAlg U1) holds (MSAlg h) # y = h * y

let h be Function of U1,U2; :: thesis: ( U1,U2 are_similar implies for o being OperSymbol of (MSSign U1)
for y being Element of Args o,(MSAlg U1) holds (MSAlg h) # y = h * y )

assume A1: U1,U2 are_similar ; :: thesis: for o being OperSymbol of (MSSign U1)
for y being Element of Args o,(MSAlg U1) holds (MSAlg h) # y = h * y

then A2: MSSign U1 = MSSign U2 by Th10;
A3: 0 in {0 } by TARSKI:def 1;
set f = MSAlg h;
let o be OperSymbol of (MSSign U1); :: thesis: for y being Element of Args o,(MSAlg U1) holds (MSAlg h) # y = h * y
let y be Element of Args o,(MSAlg U1); :: thesis: (MSAlg h) # y = h * y
reconsider f1 = (*--> 0 ) * (signature U1) as Function of (dom (signature U1)),({0 } * ) by MSUALG_1:7;
A4: ( the carrier of (MSSign U1) = {0 } & the carrier' of (MSSign U1) = dom (signature U1) & the Arity of (MSSign U1) = f1 & the ResultSort of (MSSign U1) = (dom (signature U1)) --> 0 ) by MSUALG_1:def 13;
then A5: the_arity_of o = ((*--> 0 ) * (signature U1)) . o by MSUALG_1:def 6;
reconsider f2 = (*--> 0 ) * (signature U2) as Function of (dom (signature U2)),({0 } * ) by MSUALG_1:7;
A6: ( the carrier of (MSSign U2) = {0 } & the carrier' of (MSSign U2) = dom (signature U2) & the Arity of (MSSign U2) = f2 & the ResultSort of (MSSign U2) = (dom (signature U2)) --> 0 ) by MSUALG_1:def 13;
o in dom (signature U2) by A2, A6;
then A7: o in dom (signature U1) by A1, UNIALG_2:def 2;
then o in dom f1 by FUNCT_2:def 1;
then A8: ((*--> 0 ) * (signature U1)) . o = (*--> 0 ) . ((signature U1) . o) by FUNCT_1:22;
(signature U1) . o in rng (signature U1) by A7, FUNCT_1:def 5;
then consider n being Element of NAT such that
A9: n = (signature U1) . o ;
A10: now
let m be Nat; :: thesis: ( m in dom y implies (MSAlg h) . ((the_arity_of o) /. m) = h )
assume m in dom y ; :: thesis: (MSAlg h) . ((the_arity_of o) /. m) = h
then A11: m in dom (the_arity_of o) by MSUALG_3:6;
0 is Element of {0 } by TARSKI:def 1;
then n |-> 0 is FinSequence of {0 } by FINSEQ_2:77;
then reconsider l = n |-> 0 as Element of the carrier of (MSSign U1) * by A4, FINSEQ_1:def 11;
A12: m in dom (n |-> 0 ) by A5, A8, A9, A11, PBOOLE:def 20;
A13: (the_arity_of o) /. m = l /. m by A5, A8, A9, PBOOLE:def 20;
A14: l /. m = l . m by A12, PARTFUN1:def 8;
dom (n |-> 0 ) = Seg n by FUNCOP_1:19;
then (the_arity_of o) /. m = 0 by A12, A13, A14, FUNCOP_1:13;
hence (MSAlg h) . ((the_arity_of o) /. m) = (0 .--> h) . 0 by A1, Def3, Th10
.= h by A3, FUNCOP_1:13 ;
:: thesis: verum
end;
A15: y is FinSequence of the carrier of U1 by Th14;
then A16: rng y c= the carrier of U1 by FINSEQ_1:def 4;
A17: dom y = dom (the_arity_of o) by MSUALG_3:6
.= dom (n |-> 0 ) by A5, A8, A9, PBOOLE:def 20
.= Seg n by FUNCOP_1:19 ;
set X = dom (h * y);
A18: dom ((MSAlg h) # y) = dom (the_arity_of o) by MSUALG_3:6
.= dom (n |-> 0 ) by A5, A8, A9, PBOOLE:def 20
.= Seg n by FUNCOP_1:19
.= dom (h * y) by A15, A17, ALG_1:1 ;
dom ((MSAlg h) # y) = dom (the_arity_of o) by MSUALG_3:6
.= dom (n |-> 0 ) by A5, A8, A9, PBOOLE:def 20
.= Seg n by FUNCOP_1:19 ;
then A19: (MSAlg h) # y is FinSequence by FINSEQ_1:def 2;
dom h = the carrier of U1 by FUNCT_2:def 1;
then reconsider p = h * y as FinSequence by A15, A16, FINSEQ_1:20;
A20: now
let m be Nat; :: thesis: ( m in dom y implies ((MSAlg h) # y) . m = p . m )
assume A21: m in dom y ; :: thesis: ((MSAlg h) # y) . m = p . m
then A22: m in dom (h * y) by A15, ALG_1:1;
((MSAlg h) # y) . m = ((MSAlg h) . ((the_arity_of o) /. m)) . (y . m) by A21, MSUALG_3:def 8;
hence ((MSAlg h) # y) . m = h . (y . m) by A10, A21
.= p . m by A15, A22, ALG_1:1 ;
:: thesis: verum
end;
dom (h * y) = dom y by A15, ALG_1:1;
hence (MSAlg h) # y = h * y by A18, A19, A20, FINSEQ_1:17; :: thesis: verum