let OAlph, IAlph be non empty set ; :: thesis: for tfsm1, tfsm2 being non empty Mealy-FSM of IAlph,OAlph
for q11, q12 being State of tfsm1
for Tf being Function of the carrier of tfsm1,the carrier of tfsm2 st Tf . the InitS of tfsm1 = the InitS of tfsm2 & ( for q being State of tfsm1
for s being Element of IAlph holds
( Tf . (the Tran of tfsm1 . q,s) = the Tran of tfsm2 . (Tf . q),s & the OFun of tfsm1 . q,s = the OFun of tfsm2 . (Tf . q),s ) ) holds
( q11,q12 -are_equivalent iff Tf . q11,Tf . q12 -are_equivalent )

let tfsm1, tfsm2 be non empty Mealy-FSM of IAlph,OAlph; :: thesis: for q11, q12 being State of tfsm1
for Tf being Function of the carrier of tfsm1,the carrier of tfsm2 st Tf . the InitS of tfsm1 = the InitS of tfsm2 & ( for q being State of tfsm1
for s being Element of IAlph holds
( Tf . (the Tran of tfsm1 . q,s) = the Tran of tfsm2 . (Tf . q),s & the OFun of tfsm1 . q,s = the OFun of tfsm2 . (Tf . q),s ) ) holds
( q11,q12 -are_equivalent iff Tf . q11,Tf . q12 -are_equivalent )

let q11, q12 be State of tfsm1; :: thesis: for Tf being Function of the carrier of tfsm1,the carrier of tfsm2 st Tf . the InitS of tfsm1 = the InitS of tfsm2 & ( for q being State of tfsm1
for s being Element of IAlph holds
( Tf . (the Tran of tfsm1 . q,s) = the Tran of tfsm2 . (Tf . q),s & the OFun of tfsm1 . q,s = the OFun of tfsm2 . (Tf . q),s ) ) holds
( q11,q12 -are_equivalent iff Tf . q11,Tf . q12 -are_equivalent )

let Tf be Function of the carrier of tfsm1,the carrier of tfsm2; :: thesis: ( Tf . the InitS of tfsm1 = the InitS of tfsm2 & ( for q being State of tfsm1
for s being Element of IAlph holds
( Tf . (the Tran of tfsm1 . q,s) = the Tran of tfsm2 . (Tf . q),s & the OFun of tfsm1 . q,s = the OFun of tfsm2 . (Tf . q),s ) ) implies ( q11,q12 -are_equivalent iff Tf . q11,Tf . q12 -are_equivalent ) )

set Stfsm1 = the carrier of tfsm1;
set Stfsm2 = the carrier of tfsm2;
set OF1 = the OFun of tfsm1;
set OF2 = the OFun of tfsm2;
assume A1: ( Tf . the InitS of tfsm1 = the InitS of tfsm2 & ( for q being Element of the carrier of tfsm1
for s being Element of IAlph holds
( Tf . (the Tran of tfsm1 . q,s) = the Tran of tfsm2 . (Tf . q),s & the OFun of tfsm1 . q,s = the OFun of tfsm2 . (Tf . q),s ) ) ) ; :: thesis: ( q11,q12 -are_equivalent iff Tf . q11,Tf . q12 -are_equivalent )
hereby :: thesis: ( Tf . q11,Tf . q12 -are_equivalent implies q11,q12 -are_equivalent )
assume A2: q11,q12 -are_equivalent ; :: thesis: Tf . q11,Tf . q12 -are_equivalent
reconsider Tq1 = Tf . q11 as Element of the carrier of tfsm2 ;
reconsider Tq2 = Tf . q12 as Element of the carrier of tfsm2 ;
now
let w be FinSequence of IAlph; :: thesis: Tq1,w -response = Tq2,w -response
A3: len (Tq1,w -response ) = len w by Def6
.= len (Tq2,w -response ) by Def6 ;
now
let k be Nat; :: thesis: ( 1 <= k & k <= len (Tq1,w -response ) implies (Tq1,w -response ) . k = (Tq2,w -response ) . k )
assume A4: ( 1 <= k & k <= len (Tq1,w -response ) ) ; :: thesis: (Tq1,w -response ) . k = (Tq2,w -response ) . k
len (Tq1,w -response ) = len w by Def6;
then A5: k in Seg (len w) by A4, FINSEQ_1:3;
then A6: k in Seg ((len w) + 1) by FINSEQ_2:9;
then A7: ( 1 <= k & k <= (len w) + 1 ) by FINSEQ_1:3;
A8: k in dom w by A5, FINSEQ_1:def 3;
len (q11,w -admissible ) = (len w) + 1 by Def2;
then k in dom (q11,w -admissible ) by A6, FINSEQ_1:def 3;
then reconsider q1a = (q11,w -admissible ) . k as Element of the carrier of tfsm1 by FINSEQ_2:13;
len (q12,w -admissible ) = (len w) + 1 by Def2;
then k in dom (q12,w -admissible ) by A6, FINSEQ_1:def 3;
then reconsider q2a = (q12,w -admissible ) . k as Element of the carrier of tfsm1 by FINSEQ_2:13;
reconsider wk = w . k as Element of IAlph by A8, FINSEQ_2:13;
A9: k in NAT by ORDINAL1:def 13;
thus (Tq1,w -response ) . k = the OFun of tfsm2 . [((Tq1,w -admissible ) . k),(w . k)] by A8, Def6
.= the OFun of tfsm2 . (Tf . q1a),wk by A1, A7, A9, Th60
.= the OFun of tfsm1 . q1a,wk by A1
.= (q11,w -response ) . k by A8, Def6
.= (q12,w -response ) . k by A2, Def10
.= the OFun of tfsm1 . q2a,wk by A8, Def6
.= the OFun of tfsm2 . (Tf . q2a),wk by A1
.= the OFun of tfsm2 . [((Tq2,w -admissible ) . k),(w . k)] by A1, A7, A9, Th60
.= (Tq2,w -response ) . k by A8, Def6 ; :: thesis: verum
end;
hence Tq1,w -response = Tq2,w -response by A3, FINSEQ_1:18; :: thesis: verum
end;
hence Tf . q11,Tf . q12 -are_equivalent by Def10; :: thesis: verum
end;
assume A10: Tf . q11,Tf . q12 -are_equivalent ; :: thesis: q11,q12 -are_equivalent
now
let w be FinSequence of IAlph; :: thesis: q11,w -response = q12,w -response
A11: len (q11,w -response ) = len w by Def6
.= len (q12,w -response ) by Def6 ;
now
let k be Nat; :: thesis: ( 1 <= k & k <= len (q11,w -response ) implies (q11,w -response ) . k = (q12,w -response ) . k )
assume A12: ( 1 <= k & k <= len (q11,w -response ) ) ; :: thesis: (q11,w -response ) . k = (q12,w -response ) . k
A13: k in NAT by ORDINAL1:def 13;
len (q11,w -response ) = len w by Def6;
then A14: k in Seg (len w) by A12, FINSEQ_1:3;
then A15: k in Seg ((len w) + 1) by FINSEQ_2:9;
then A16: ( 1 <= k & k <= (len w) + 1 ) by FINSEQ_1:3;
A17: k in dom w by A14, FINSEQ_1:def 3;
len (q11,w -admissible ) = (len w) + 1 by Def2;
then k in dom (q11,w -admissible ) by A15, FINSEQ_1:def 3;
then reconsider q1a = (q11,w -admissible ) . k as Element of the carrier of tfsm1 by FINSEQ_2:13;
len (q12,w -admissible ) = (len w) + 1 by Def2;
then k in dom (q12,w -admissible ) by A15, FINSEQ_1:def 3;
then reconsider q2a = (q12,w -admissible ) . k as Element of the carrier of tfsm1 by FINSEQ_2:13;
reconsider wk = w . k as Element of IAlph by A17, FINSEQ_2:13;
thus (q11,w -response ) . k = the OFun of tfsm1 . ((q11,w -admissible ) . k),(w . k) by A17, Def6
.= the OFun of tfsm2 . (Tf . q1a),wk by A1
.= the OFun of tfsm2 . [(((Tf . q11),w -admissible ) . k),wk] by A1, A13, A16, Th60
.= ((Tf . q11),w -response ) . k by A17, Def6
.= ((Tf . q12),w -response ) . k by A10, Def10
.= the OFun of tfsm2 . [(((Tf . q12),w -admissible ) . k),(w . k)] by A17, Def6
.= the OFun of tfsm2 . (Tf . q2a),wk by A1, A13, A16, Th60
.= the OFun of tfsm1 . q2a,(w . k) by A1
.= (q12,w -response ) . k by A17, Def6 ; :: thesis: verum
end;
hence q11,w -response = q12,w -response by A11, FINSEQ_1:18; :: thesis: verum
end;
hence q11,q12 -are_equivalent by Def10; :: thesis: verum