Metamath Proof Explorer


Theorem oftpos

Description: The transposition of the value of a function operation for two functions is the value of the function operation for the two functions transposed. (Contributed by Stefan O'Rear, 17-Jul-2018)

Ref Expression
Assertion oftpos F V G W tpos F R f G = tpos F R f tpos G

Proof

Step Hyp Ref Expression
1 elex F V F V
2 1 adantr F V G W F V
3 elex G W G V
4 3 adantl F V G W G V
5 funmpt Fun x V × V x -1
6 5 a1i F V G W Fun x V × V x -1
7 dftpos4 tpos F = F x V × V x -1
8 tposexg F V tpos F V
9 8 adantr F V G W tpos F V
10 7 9 eqeltrrid F V G W F x V × V x -1 V
11 dftpos4 tpos G = G x V × V x -1
12 tposexg G W tpos G V
13 12 adantl F V G W tpos G V
14 11 13 eqeltrrid F V G W G x V × V x -1 V
15 ofco2 F V G V Fun x V × V x -1 F x V × V x -1 V G x V × V x -1 V F R f G x V × V x -1 = F x V × V x -1 R f G x V × V x -1
16 2 4 6 10 14 15 syl23anc F V G W F R f G x V × V x -1 = F x V × V x -1 R f G x V × V x -1
17 dftpos4 tpos F R f G = F R f G x V × V x -1
18 7 11 oveq12i tpos F R f tpos G = F x V × V x -1 R f G x V × V x -1
19 16 17 18 3eqtr4g F V G W tpos F R f G = tpos F R f tpos G