let I be non empty set ; :: thesis: for S being non empty FSM of I st S is regular & S is calculating_type holds
for s, s1, s2 being Element of I
for q being State of S st the Tran of S . [the InitS of S,s1] <> the Tran of S . [the InitS of S,s2] holds
the Tran of S . [q,s] <> the InitS of S

let S be non empty FSM of I; :: thesis: ( S is regular & S is calculating_type implies for s, s1, s2 being Element of I
for q being State of S st the Tran of S . [the InitS of S,s1] <> the Tran of S . [the InitS of S,s2] holds
the Tran of S . [q,s] <> the InitS of S )

assume A1: ( S is regular & S is calculating_type ) ; :: thesis: for s, s1, s2 being Element of I
for q being State of S st the Tran of S . [the InitS of S,s1] <> the Tran of S . [the InitS of S,s2] holds
the Tran of S . [q,s] <> the InitS of S

let s, s1, s2 be Element of I; :: thesis: for q being State of S st the Tran of S . [the InitS of S,s1] <> the Tran of S . [the InitS of S,s2] holds
the Tran of S . [q,s] <> the InitS of S

let q be State of S; :: thesis: ( the Tran of S . [the InitS of S,s1] <> the Tran of S . [the InitS of S,s2] implies the Tran of S . [q,s] <> the InitS of S )
assume A2: the Tran of S . [the InitS of S,s1] <> the Tran of S . [the InitS of S,s2] ; :: thesis: the Tran of S . [q,s] <> the InitS of S
q is accessible by A1, Def4;
then consider w being FinSequence of I such that
A3: the InitS of S,w -leads_to q by Def3;
A4: (GEN w,the InitS of S) . ((len w) + 1) = q by A3, FSM_1:def 3;
assume A5: the Tran of S . [q,s] = the InitS of S ; :: thesis: contradiction
reconsider w1 = <*s,s1*>, w2 = <*s,s2*> as FinSequence of I ;
A6: GEN w1,q = <*q,the InitS of S,(the Tran of S . [the InitS of S,s1])*> by A5, Th2;
GEN w2,q = <*q,the InitS of S,(the Tran of S . [the InitS of S,s2])*> by A5, Th2;
then A7: ( (GEN w1,q) . 3 = the Tran of S . [the InitS of S,s1] & (GEN w2,q) . 3 = the Tran of S . [the InitS of S,s2] ) by A6, FINSEQ_1:62;
A8: ( len w1 = 2 & len w2 = 2 ) by FINSEQ_1:61;
then ( 1 <= 3 & 3 <= (len w1) + 1 & 3 <= (len w2) + 1 ) ;
then A9: ( (GEN (w ^ w1),the InitS of S) . ((len w) + 3) = the Tran of S . [the InitS of S,s1] & (GEN (w ^ w2),the InitS of S) . ((len w) + 3) = the Tran of S . [the InitS of S,s2] ) by A3, A7, FSM_1:22;
per cases ( w = {} or w <> {} ) ;
suppose w = {} ; :: thesis: contradiction
then A10: len w = 0 ;
A11: ( GEN w1,the InitS of S = <*the InitS of S,(the Tran of S . [the InitS of S,s]),(the Tran of S . [(the Tran of S . [the InitS of S,s]),s1])*> & GEN w2,the InitS of S = <*the InitS of S,(the Tran of S . [the InitS of S,s]),(the Tran of S . [(the Tran of S . [the InitS of S,s]),s2])*> ) by Th2;
A12: ( w1 . 1 = s & w2 . 1 = s ) by FINSEQ_1:61;
A13: ( 3 <= (len w1) + 1 & 3 <= (len w2) + 1 ) by A8;
A14: (GEN w1,the InitS of S) . 3 = the Tran of S . [(the Tran of S . [the InitS of S,s]),s1] by A11, FINSEQ_1:62
.= the Tran of S . [the InitS of S,s1] by A4, A5, A10, FSM_1:def 2 ;
(GEN w2,the InitS of S) . 3 = the Tran of S . [(the Tran of S . [the InitS of S,s]),s2] by A11, FINSEQ_1:62
.= the Tran of S . [the InitS of S,s2] by A4, A5, A10, FSM_1:def 2 ;
hence contradiction by A1, A2, A12, A13, A14, Def1; :: thesis: verum
end;
suppose w <> {} ; :: thesis: contradiction
then consider s' being set , w' being FinSequence such that
A15: ( w = <*s'*> ^ w' & len w = (len w') + 1 ) by REWRITE1:5;
dom <*s'*> = Seg 1 by FINSEQ_1:def 8;
then A16: 1 in dom <*s'*> by FINSEQ_1:3;
then A17: w . 1 = <*s'*> . 1 by A15, FINSEQ_1:def 7
.= s' by FINSEQ_1:def 8 ;
dom <*s'*> c= dom w by A15, FINSEQ_1:39;
then A18: ( (w ^ w1) . 1 = s' & (w ^ w2) . 1 = s' ) by A16, A17, FINSEQ_1:def 7;
( (len (w ^ w1)) + 1 = ((len w) + 2) + 1 & (len (w ^ w2)) + 1 = ((len w) + 2) + 1 ) by A8, FINSEQ_1:35;
hence contradiction by A1, A2, A9, A18, Def1; :: thesis: verum
end;
end;