Metamath Proof Explorer


Theorem hial2eq2

Description: Two vectors whose inner product is always equal are equal. (Contributed by NM, 28-Jan-2006) (New usage is discouraged.)

Ref Expression
Assertion hial2eq2 ABxxihA=xihBA=B

Proof

Step Hyp Ref Expression
1 ax-his1 AxAihx=xihA
2 ax-his1 BxBihx=xihB
3 1 2 eqeqan12d AxBxAihx=BihxxihA=xihB
4 hicl xAxihA
5 4 ancoms AxxihA
6 hicl xBxihB
7 6 ancoms BxxihB
8 cj11 xihAxihBxihA=xihBxihA=xihB
9 5 7 8 syl2an AxBxxihA=xihBxihA=xihB
10 3 9 bitr2d AxBxxihA=xihBAihx=Bihx
11 10 anandirs ABxxihA=xihBAihx=Bihx
12 11 ralbidva ABxxihA=xihBxAihx=Bihx
13 hial2eq ABxAihx=BihxA=B
14 12 13 bitrd ABxxihA=xihBA=B