Theorem grpressid 13478

Description: A group restricted to its base set is a group. It will usually be the original group exactly, of course, but to show that needs additional conditions such as those in strressid 12988. (Contributed by Jim Kingdon, 28-Feb-2025.)

Hypothesis

Ref	Expression
grpressid.b	|- B = ( Base ` G )

Assertion

Ref	Expression
grpressid	|- ( G e. Grp -> ( G ↾s B ) e. Grp )

Proof of Theorem grpressid

Dummy variables x y z are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		inidm 3386	. . 3 |- ( B i^i B ) = B
2		eqidd 2207	. . . 4 |- ( G e. Grp -> ( G ↾s B ) = ( G ↾s B ) )
3		grpressid.b	. . . . 5 |- B = ( Base ` G )
4	3	a1i 9	. . . 4 |- ( G e. Grp -> B = ( Base ` G ) )
5		id 19	. . . 4 |- ( G e. Grp -> G e. Grp )
6		basfn 12975	. . . . . 6 |- Base Fn _V
7		elex 2785	. . . . . 6 |- ( G e. Grp -> G e. _V )
8		funfvex 5611	. . . . . . 7 |- ( ( Fun Base /\ G e. dom Base ) -> ( Base ` G ) e. _V )
9	8	funfni 5390	. . . . . 6 |- ( ( Base Fn _V /\ G e. _V ) -> ( Base ` G ) e. _V )
10	6, 7, 9	sylancr 414	. . . . 5 |- ( G e. Grp -> ( Base ` G ) e. _V )
11	3, 10	eqeltrid 2293	. . . 4 |- ( G e. Grp -> B e. _V )
12	2, 4, 5, 11	ressbasd 12984	. . 3 |- ( G e. Grp -> ( B i^i B ) = ( Base ` ( G ↾s B ) ) )
13	1, 12	eqtr3id 2253	. 2 |- ( G e. Grp -> B = ( Base ` ( G ↾s B ) ) )
14		eqidd 2207	. . 3 |- ( G e. Grp -> ( +g ` G ) = ( +g ` G ) )
15	2, 14, 11, 7	ressplusgd 13046	. 2 |- ( G e. Grp -> ( +g ` G ) = ( +g ` ( G ↾s B ) ) )
16		eqid 2206	. . 3 |- ( +g ` G ) = ( +g ` G )
17	3, 16	grpcl 13425	. 2 |- ( ( G e. Grp /\ x e. B /\ y e. B ) -> ( x ( +g ` G ) y ) e. B )
18	3, 16	grpass 13426	. 2 |- ( ( G e. Grp /\ ( x e. B /\ y e. B /\ z e. B ) ) -> ( ( x ( +g ` G ) y ) ( +g ` G ) z ) = ( x ( +g ` G ) ( y ( +g ` G ) z ) ) )
19		eqid 2206	. . 3 |- ( 0g ` G ) = ( 0g ` G )
20	3, 19	grpidcl 13446	. 2 |- ( G e. Grp -> ( 0g ` G ) e. B )
21	3, 16, 19	grplid 13448	. 2 |- ( ( G e. Grp /\ x e. B ) -> ( ( 0g ` G ) ( +g ` G ) x ) = x )
22		eqid 2206	. . 3 |- ( invg ` G ) = ( invg ` G )
23	3, 22	grpinvcl 13465	. 2 |- ( ( G e. Grp /\ x e. B ) -> ( ( invg ` G ) ` x ) e. B )
24	3, 16, 19, 22	grplinv 13467	. 2 |- ( ( G e. Grp /\ x e. B ) -> ( ( ( invg ` G ) ` x ) ( +g ` G ) x ) = ( 0g ` G ) )
25	13, 15, 17, 18, 20, 21, 23, 24	isgrpd 13440	1 |- ( G e. Grp -> ( G ↾s B ) e. Grp )

Syntax hints:   -> wi 4   = wceq 1373   e. wcel 2177   _Vcvv 2773   i^i cin 3169   Fn wfn 5280   ` cfv 5285  (class class class)co 5962   Basecbs 12917   ↾_s cress 12918   +g cplusg 12994   0gc0g 13173   Grpcgrp 13417   invgcminusg 13418

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 615  ax-in2 616  ax-io 711  ax-5 1471  ax-7 1472  ax-gen 1473  ax-ie1 1517  ax-ie2 1518  ax-8 1528  ax-10 1529  ax-11 1530  ax-i12 1531  ax-bndl 1533  ax-4 1534  ax-17 1550  ax-i9 1554  ax-ial 1558  ax-i5r 1559  ax-13 2179  ax-14 2180  ax-ext 2188  ax-coll 4170  ax-sep 4173  ax-pow 4229  ax-pr 4264  ax-un 4493  ax-setind 4598  ax-cnex 8046  ax-resscn 8047  ax-1cn 8048  ax-1re 8049  ax-icn 8050  ax-addcl 8051  ax-addrcl 8052  ax-mulcl 8053  ax-addcom 8055  ax-addass 8057  ax-i2m1 8060  ax-0lt1 8061  ax-0id 8063  ax-rnegex 8064  ax-pre-ltirr 8067  ax-pre-ltadd 8071

This theorem depends on definitions:  df-bi 117  df-3an 983  df-tru 1376  df-fal 1379  df-nf 1485  df-sb 1787  df-eu 2058  df-mo 2059  df-clab 2193  df-cleq 2199  df-clel 2202  df-nfc 2338  df-ne 2378  df-nel 2473  df-ral 2490  df-rex 2491  df-reu 2492  df-rmo 2493  df-rab 2494  df-v 2775  df-sbc 3003  df-csb 3098  df-dif 3172  df-un 3174  df-in 3176  df-ss 3183  df-nul 3465  df-pw 3623  df-sn 3644  df-pr 3645  df-op 3647  df-uni 3860  df-int 3895  df-iun 3938  df-br 4055  df-opab 4117  df-mpt 4118  df-id 4353  df-xp 4694  df-rel 4695  df-cnv 4696  df-co 4697  df-dm 4698  df-rn 4699  df-res 4700  df-ima 4701  df-iota 5246  df-fun 5287  df-fn 5288  df-f 5289  df-f1 5290  df-fo 5291  df-f1o 5292  df-fv 5293  df-riota 5917  df-ov 5965  df-oprab 5966  df-mpo 5967  df-pnf 8139  df-mnf 8140  df-ltxr 8142  df-inn 9067  df-2 9125  df-ndx 12920  df-slot 12921  df-base 12923  df-sets 12924  df-iress 12925  df-plusg 13007  df-0g 13175  df-mgm 13273  df-sgrp 13319  df-mnd 13334  df-grp 13420  df-minusg 13421

This theorem is referenced by:  subgid  13596  ablressid  13756  ringressid  13910