Metamath Proof Explorer


Theorem kbass4

Description: Dirac bra-ket associative law <. A | B >. <. C | D >. = <. A | ( | B >. <. C | D >. ) . (Contributed by NM, 30-May-2006) (New usage is discouraged.)

Ref Expression
Assertion kbass4 A B C D bra A B bra C D = bra A bra C D B

Proof

Step Hyp Ref Expression
1 bracl A B bra A B
2 bracl C D bra C D
3 mulcom bra A B bra C D bra A B bra C D = bra C D bra A B
4 1 2 3 syl2an A B C D bra A B bra C D = bra C D bra A B
5 bralnfn A bra A LinFn
6 5 ad2antrr A B C D bra A LinFn
7 2 adantl A B C D bra C D
8 simplr A B C D B
9 lnfnmul bra A LinFn bra C D B bra A bra C D B = bra C D bra A B
10 6 7 8 9 syl3anc A B C D bra A bra C D B = bra C D bra A B
11 4 10 eqtr4d A B C D bra A B bra C D = bra A bra C D B