Metamath Proof Explorer


Theorem grpplusgx

Description: The operation of an explicitly given group. Note: This theorem has hard-coded structure indices for demonstration purposes. It is not intended for general use; use grpplusg instead. (New usage is discouraged.) (Contributed by NM, 17-Oct-2012)

Ref Expression
Hypotheses grpstrx.b
|- B e. _V
grpstrx.p
|- .+ e. _V
grpstrx.g
|- G = { <. 1 , B >. , <. 2 , .+ >. }
Assertion grpplusgx
|- .+ = ( +g ` G )

Proof

Step Hyp Ref Expression
1 grpstrx.b
 |-  B e. _V
2 grpstrx.p
 |-  .+ e. _V
3 grpstrx.g
 |-  G = { <. 1 , B >. , <. 2 , .+ >. }
4 basendx
 |-  ( Base ` ndx ) = 1
5 4 opeq1i
 |-  <. ( Base ` ndx ) , B >. = <. 1 , B >.
6 plusgndx
 |-  ( +g ` ndx ) = 2
7 6 opeq1i
 |-  <. ( +g ` ndx ) , .+ >. = <. 2 , .+ >.
8 5 7 preq12i
 |-  { <. ( Base ` ndx ) , B >. , <. ( +g ` ndx ) , .+ >. } = { <. 1 , B >. , <. 2 , .+ >. }
9 3 8 eqtr4i
 |-  G = { <. ( Base ` ndx ) , B >. , <. ( +g ` ndx ) , .+ >. }
10 9 grpplusg
 |-  ( .+ e. _V -> .+ = ( +g ` G ) )
11 2 10 ax-mp
 |-  .+ = ( +g ` G )