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 ABCDbraABbraCD=braAbraCDB

Proof

Step Hyp Ref Expression
1 bracl ABbraAB
2 bracl CDbraCD
3 mulcom braABbraCDbraABbraCD=braCDbraAB
4 1 2 3 syl2an ABCDbraABbraCD=braCDbraAB
5 bralnfn AbraALinFn
6 5 ad2antrr ABCDbraALinFn
7 2 adantl ABCDbraCD
8 simplr ABCDB
9 lnfnmul braALinFnbraCDBbraAbraCDB=braCDbraAB
10 6 7 8 9 syl3anc ABCDbraAbraCDB=braCDbraAB
11 4 10 eqtr4d ABCDbraABbraCD=braAbraCDB