let D be non empty set ; :: thesis: for B being BinOp of D
for d1, d2 being Element of D
for f being FinSequence of D
for F being finite set
for E being Enumeration of F st ( B is having_a_unity or len f >= 1 ) & B is associative & not 1 + (len f) in union F & not 2 + (len f) in union F holds
B "**" ((SignGenOp (((f ^ <*d1*>) ^ <*d2*>),B,F)) * E) = B "**" ((SignGenOp ((f ^ <*(B . (d1,d2))*>),B,F)) * E)
let B be BinOp of D; :: thesis: for d1, d2 being Element of D
for f being FinSequence of D
for F being finite set
for E being Enumeration of F st ( B is having_a_unity or len f >= 1 ) & B is associative & not 1 + (len f) in union F & not 2 + (len f) in union F holds
B "**" ((SignGenOp (((f ^ <*d1*>) ^ <*d2*>),B,F)) * E) = B "**" ((SignGenOp ((f ^ <*(B . (d1,d2))*>),B,F)) * E)
let d1, d2 be Element of D; :: thesis: for f being FinSequence of D
for F being finite set
for E being Enumeration of F st ( B is having_a_unity or len f >= 1 ) & B is associative & not 1 + (len f) in union F & not 2 + (len f) in union F holds
B "**" ((SignGenOp (((f ^ <*d1*>) ^ <*d2*>),B,F)) * E) = B "**" ((SignGenOp ((f ^ <*(B . (d1,d2))*>),B,F)) * E)
let f be FinSequence of D; :: thesis: for F being finite set
for E being Enumeration of F st ( B is having_a_unity or len f >= 1 ) & B is associative & not 1 + (len f) in union F & not 2 + (len f) in union F holds
B "**" ((SignGenOp (((f ^ <*d1*>) ^ <*d2*>),B,F)) * E) = B "**" ((SignGenOp ((f ^ <*(B . (d1,d2))*>),B,F)) * E)
let F be finite set ; :: thesis: for E being Enumeration of F st ( B is having_a_unity or len f >= 1 ) & B is associative & not 1 + (len f) in union F & not 2 + (len f) in union F holds
B "**" ((SignGenOp (((f ^ <*d1*>) ^ <*d2*>),B,F)) * E) = B "**" ((SignGenOp ((f ^ <*(B . (d1,d2))*>),B,F)) * E)
let E be Enumeration of F; :: thesis: ( ( B is having_a_unity or len f >= 1 ) & B is associative & not 1 + (len f) in union F & not 2 + (len f) in union F implies B "**" ((SignGenOp (((f ^ <*d1*>) ^ <*d2*>),B,F)) * E) = B "**" ((SignGenOp ((f ^ <*(B . (d1,d2))*>),B,F)) * E) )
assume that
A1: ( B is having_a_unity or len f >= 1 ) and
A2: B is associative and
A3: ( not 1 + (len f) in union F & not 2 + (len f) in union F ) ; :: thesis: B "**" ((SignGenOp (((f ^ <*d1*>) ^ <*d2*>),B,F)) * E) = B "**" ((SignGenOp ((f ^ <*(B . (d1,d2))*>),B,F)) * E)
A4: len (f ^ <*d1*>) = 1 + (len f) by FINSEQ_2:16;
then not 1 + (len (f ^ <*d1*>)) in union F by A3;
hence B "**" ((SignGenOp (((f ^ <*d1*>) ^ <*d2*>),B,F)) * E) = B [:] ((B "**" ((SignGenOp ((f ^ <*d1*>),B,F)) * E)),d2) by NAT_1:11, Th82, A4
.= B [:] ((B [:] ((B "**" ((SignGenOp (f,B,F)) * E)),d1)),d2) by A1, Th82, A3
.= B [:] ((B "**" ((SignGenOp (f,B,F)) * E)),(B . (d1,d2))) by A2, FUNCOP_1:63
.= B "**" ((SignGenOp ((f ^ <*(B . (d1,d2))*>),B,F)) * E) by A1, Th82, A3 ;
:: thesis: verum