Metamath Proof Explorer


Theorem mgplemOLD

Description: Obsolete version of setsplusg as of 18-Oct-2024. Lemma for mgpbas . (Contributed by Mario Carneiro, 5-Oct-2015) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Hypotheses mgpbas.1 𝑀 = ( mulGrp ‘ 𝑅 )
mgplemOLD.2 𝐸 = Slot 𝑁
mgplemOLD.3 𝑁 ∈ ℕ
mgplemOLD.4 𝑁 ≠ 2
Assertion mgplemOLD ( 𝐸𝑅 ) = ( 𝐸𝑀 )

Proof

Step Hyp Ref Expression
1 mgpbas.1 𝑀 = ( mulGrp ‘ 𝑅 )
2 mgplemOLD.2 𝐸 = Slot 𝑁
3 mgplemOLD.3 𝑁 ∈ ℕ
4 mgplemOLD.4 𝑁 ≠ 2
5 2 3 ndxid 𝐸 = Slot ( 𝐸 ‘ ndx )
6 2 3 ndxarg ( 𝐸 ‘ ndx ) = 𝑁
7 plusgndx ( +g ‘ ndx ) = 2
8 6 7 neeq12i ( ( 𝐸 ‘ ndx ) ≠ ( +g ‘ ndx ) ↔ 𝑁 ≠ 2 )
9 4 8 mpbir ( 𝐸 ‘ ndx ) ≠ ( +g ‘ ndx )
10 5 9 setsnid ( 𝐸𝑅 ) = ( 𝐸 ‘ ( 𝑅 sSet ⟨ ( +g ‘ ndx ) , ( .r𝑅 ) ⟩ ) )
11 eqid ( .r𝑅 ) = ( .r𝑅 )
12 1 11 mgpval 𝑀 = ( 𝑅 sSet ⟨ ( +g ‘ ndx ) , ( .r𝑅 ) ⟩ )
13 12 fveq2i ( 𝐸𝑀 ) = ( 𝐸 ‘ ( 𝑅 sSet ⟨ ( +g ‘ ndx ) , ( .r𝑅 ) ⟩ ) )
14 10 13 eqtr4i ( 𝐸𝑅 ) = ( 𝐸𝑀 )