Metamath Proof Explorer


Theorem grplactcnv

Description: The left group action of element A of group G maps the underlying set X of G one-to-one onto itself. (Contributed by Paul Chapman, 18-Mar-2008) (Proof shortened by Mario Carneiro, 14-Aug-2015)

Ref Expression
Hypotheses grplact.1 𝐹 = ( 𝑔𝑋 ↦ ( 𝑎𝑋 ↦ ( 𝑔 + 𝑎 ) ) )
grplact.2 𝑋 = ( Base ‘ 𝐺 )
grplact.3 + = ( +g𝐺 )
grplactcnv.4 𝐼 = ( invg𝐺 )
Assertion grplactcnv ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) → ( ( 𝐹𝐴 ) : 𝑋1-1-onto𝑋 ( 𝐹𝐴 ) = ( 𝐹 ‘ ( 𝐼𝐴 ) ) ) )

Proof

Step Hyp Ref Expression
1 grplact.1 𝐹 = ( 𝑔𝑋 ↦ ( 𝑎𝑋 ↦ ( 𝑔 + 𝑎 ) ) )
2 grplact.2 𝑋 = ( Base ‘ 𝐺 )
3 grplact.3 + = ( +g𝐺 )
4 grplactcnv.4 𝐼 = ( invg𝐺 )
5 eqid ( 𝑎𝑋 ↦ ( 𝐴 + 𝑎 ) ) = ( 𝑎𝑋 ↦ ( 𝐴 + 𝑎 ) )
6 2 3 grpcl ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋𝑎𝑋 ) → ( 𝐴 + 𝑎 ) ∈ 𝑋 )
7 6 3expa ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ 𝑎𝑋 ) → ( 𝐴 + 𝑎 ) ∈ 𝑋 )
8 2 4 grpinvcl ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) → ( 𝐼𝐴 ) ∈ 𝑋 )
9 2 3 grpcl ( ( 𝐺 ∈ Grp ∧ ( 𝐼𝐴 ) ∈ 𝑋𝑏𝑋 ) → ( ( 𝐼𝐴 ) + 𝑏 ) ∈ 𝑋 )
10 9 3expa ( ( ( 𝐺 ∈ Grp ∧ ( 𝐼𝐴 ) ∈ 𝑋 ) ∧ 𝑏𝑋 ) → ( ( 𝐼𝐴 ) + 𝑏 ) ∈ 𝑋 )
11 8 10 syldanl ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ 𝑏𝑋 ) → ( ( 𝐼𝐴 ) + 𝑏 ) ∈ 𝑋 )
12 eqcom ( 𝑎 = ( ( 𝐼𝐴 ) + 𝑏 ) ↔ ( ( 𝐼𝐴 ) + 𝑏 ) = 𝑎 )
13 eqid ( 0g𝐺 ) = ( 0g𝐺 )
14 2 3 13 4 grplinv ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) → ( ( 𝐼𝐴 ) + 𝐴 ) = ( 0g𝐺 ) )
15 14 adantr ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → ( ( 𝐼𝐴 ) + 𝐴 ) = ( 0g𝐺 ) )
16 15 oveq1d ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → ( ( ( 𝐼𝐴 ) + 𝐴 ) + 𝑎 ) = ( ( 0g𝐺 ) + 𝑎 ) )
17 simpll ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → 𝐺 ∈ Grp )
18 8 adantr ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → ( 𝐼𝐴 ) ∈ 𝑋 )
19 simplr ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → 𝐴𝑋 )
20 simprl ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → 𝑎𝑋 )
21 2 3 grpass ( ( 𝐺 ∈ Grp ∧ ( ( 𝐼𝐴 ) ∈ 𝑋𝐴𝑋𝑎𝑋 ) ) → ( ( ( 𝐼𝐴 ) + 𝐴 ) + 𝑎 ) = ( ( 𝐼𝐴 ) + ( 𝐴 + 𝑎 ) ) )
22 17 18 19 20 21 syl13anc ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → ( ( ( 𝐼𝐴 ) + 𝐴 ) + 𝑎 ) = ( ( 𝐼𝐴 ) + ( 𝐴 + 𝑎 ) ) )
23 2 3 13 grplid ( ( 𝐺 ∈ Grp ∧ 𝑎𝑋 ) → ( ( 0g𝐺 ) + 𝑎 ) = 𝑎 )
24 23 ad2ant2r ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → ( ( 0g𝐺 ) + 𝑎 ) = 𝑎 )
25 16 22 24 3eqtr3rd ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → 𝑎 = ( ( 𝐼𝐴 ) + ( 𝐴 + 𝑎 ) ) )
26 25 eqeq2d ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → ( ( ( 𝐼𝐴 ) + 𝑏 ) = 𝑎 ↔ ( ( 𝐼𝐴 ) + 𝑏 ) = ( ( 𝐼𝐴 ) + ( 𝐴 + 𝑎 ) ) ) )
27 12 26 syl5bb ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → ( 𝑎 = ( ( 𝐼𝐴 ) + 𝑏 ) ↔ ( ( 𝐼𝐴 ) + 𝑏 ) = ( ( 𝐼𝐴 ) + ( 𝐴 + 𝑎 ) ) ) )
28 simprr ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → 𝑏𝑋 )
29 7 adantrr ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → ( 𝐴 + 𝑎 ) ∈ 𝑋 )
30 2 3 grplcan ( ( 𝐺 ∈ Grp ∧ ( 𝑏𝑋 ∧ ( 𝐴 + 𝑎 ) ∈ 𝑋 ∧ ( 𝐼𝐴 ) ∈ 𝑋 ) ) → ( ( ( 𝐼𝐴 ) + 𝑏 ) = ( ( 𝐼𝐴 ) + ( 𝐴 + 𝑎 ) ) ↔ 𝑏 = ( 𝐴 + 𝑎 ) ) )
31 17 28 29 18 30 syl13anc ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → ( ( ( 𝐼𝐴 ) + 𝑏 ) = ( ( 𝐼𝐴 ) + ( 𝐴 + 𝑎 ) ) ↔ 𝑏 = ( 𝐴 + 𝑎 ) ) )
32 27 31 bitrd ( ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) ∧ ( 𝑎𝑋𝑏𝑋 ) ) → ( 𝑎 = ( ( 𝐼𝐴 ) + 𝑏 ) ↔ 𝑏 = ( 𝐴 + 𝑎 ) ) )
33 5 7 11 32 f1ocnv2d ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) → ( ( 𝑎𝑋 ↦ ( 𝐴 + 𝑎 ) ) : 𝑋1-1-onto𝑋 ( 𝑎𝑋 ↦ ( 𝐴 + 𝑎 ) ) = ( 𝑏𝑋 ↦ ( ( 𝐼𝐴 ) + 𝑏 ) ) ) )
34 1 2 grplactfval ( 𝐴𝑋 → ( 𝐹𝐴 ) = ( 𝑎𝑋 ↦ ( 𝐴 + 𝑎 ) ) )
35 34 adantl ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) → ( 𝐹𝐴 ) = ( 𝑎𝑋 ↦ ( 𝐴 + 𝑎 ) ) )
36 f1oeq1 ( ( 𝐹𝐴 ) = ( 𝑎𝑋 ↦ ( 𝐴 + 𝑎 ) ) → ( ( 𝐹𝐴 ) : 𝑋1-1-onto𝑋 ↔ ( 𝑎𝑋 ↦ ( 𝐴 + 𝑎 ) ) : 𝑋1-1-onto𝑋 ) )
37 35 36 syl ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) → ( ( 𝐹𝐴 ) : 𝑋1-1-onto𝑋 ↔ ( 𝑎𝑋 ↦ ( 𝐴 + 𝑎 ) ) : 𝑋1-1-onto𝑋 ) )
38 35 cnveqd ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) → ( 𝐹𝐴 ) = ( 𝑎𝑋 ↦ ( 𝐴 + 𝑎 ) ) )
39 1 2 grplactfval ( ( 𝐼𝐴 ) ∈ 𝑋 → ( 𝐹 ‘ ( 𝐼𝐴 ) ) = ( 𝑎𝑋 ↦ ( ( 𝐼𝐴 ) + 𝑎 ) ) )
40 oveq2 ( 𝑎 = 𝑏 → ( ( 𝐼𝐴 ) + 𝑎 ) = ( ( 𝐼𝐴 ) + 𝑏 ) )
41 40 cbvmptv ( 𝑎𝑋 ↦ ( ( 𝐼𝐴 ) + 𝑎 ) ) = ( 𝑏𝑋 ↦ ( ( 𝐼𝐴 ) + 𝑏 ) )
42 39 41 eqtrdi ( ( 𝐼𝐴 ) ∈ 𝑋 → ( 𝐹 ‘ ( 𝐼𝐴 ) ) = ( 𝑏𝑋 ↦ ( ( 𝐼𝐴 ) + 𝑏 ) ) )
43 8 42 syl ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) → ( 𝐹 ‘ ( 𝐼𝐴 ) ) = ( 𝑏𝑋 ↦ ( ( 𝐼𝐴 ) + 𝑏 ) ) )
44 38 43 eqeq12d ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) → ( ( 𝐹𝐴 ) = ( 𝐹 ‘ ( 𝐼𝐴 ) ) ↔ ( 𝑎𝑋 ↦ ( 𝐴 + 𝑎 ) ) = ( 𝑏𝑋 ↦ ( ( 𝐼𝐴 ) + 𝑏 ) ) ) )
45 37 44 anbi12d ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) → ( ( ( 𝐹𝐴 ) : 𝑋1-1-onto𝑋 ( 𝐹𝐴 ) = ( 𝐹 ‘ ( 𝐼𝐴 ) ) ) ↔ ( ( 𝑎𝑋 ↦ ( 𝐴 + 𝑎 ) ) : 𝑋1-1-onto𝑋 ( 𝑎𝑋 ↦ ( 𝐴 + 𝑎 ) ) = ( 𝑏𝑋 ↦ ( ( 𝐼𝐴 ) + 𝑏 ) ) ) ) )
46 33 45 mpbird ( ( 𝐺 ∈ Grp ∧ 𝐴𝑋 ) → ( ( 𝐹𝐴 ) : 𝑋1-1-onto𝑋 ( 𝐹𝐴 ) = ( 𝐹 ‘ ( 𝐼𝐴 ) ) ) )