Theorem unitinvinv 14103

Description: The inverse of the inverse of a unit is the same element. (Contributed by Mario Carneiro, 4-Dec-2014.)

Hypotheses

Ref	Expression
unitinvcl.1	|- U = (Unit ` R )
unitinvcl.2	|- I = ( invr ` R )

Assertion

Ref	Expression
unitinvinv	|- ( ( R e. Ring /\ X e. U ) -> ( I ` ( I ` X ) ) = X )

Proof of Theorem unitinvinv

Step	Hyp	Ref	Expression
1		unitinvcl.1	. . . . . . 7 |- U = (Unit ` R )
2	1	a1i 9	. . . . . 6 |- ( R e. Ring -> U = (Unit ` R ) )
3		eqid 2229	. . . . . . 7 |- ( (mulGrp ` R ) ↾s U ) = ( (mulGrp ` R ) ↾s U )
4	3	a1i 9	. . . . . 6 |- ( R e. Ring -> ( (mulGrp ` R ) ↾s U ) = ( (mulGrp ` R ) ↾s U ) )
5		ringsrg 14025	. . . . . 6 |- ( R e. Ring -> R e. SRing )
6	2, 4, 5	unitgrpbasd 14094	. . . . 5 |- ( R e. Ring -> U = ( Base ` ( (mulGrp ` R ) ↾s U ) ) )
7	6	eleq2d 2299	. . . 4 |- ( R e. Ring -> ( X e. U <-> X e. ( Base ` ( (mulGrp ` R ) ↾s U ) ) ) )
8	7	pm5.32i 454	. . 3 |- ( ( R e. Ring /\ X e. U ) <-> ( R e. Ring /\ X e. ( Base ` ( (mulGrp ` R ) ↾s U ) ) ) )
9	1, 3	unitgrp 14095	. . . 4 |- ( R e. Ring -> ( (mulGrp ` R ) ↾s U ) e. Grp )
10		eqid 2229	. . . . 5 |- ( Base ` ( (mulGrp ` R ) ↾s U ) ) = ( Base ` ( (mulGrp ` R ) ↾s U ) )
11		eqid 2229	. . . . 5 |- ( invg ` ( (mulGrp ` R ) ↾s U ) ) = ( invg ` ( (mulGrp ` R ) ↾s U ) )
12	10, 11	grpinvinv 13615	. . . 4 |- ( ( ( (mulGrp ` R ) ↾s U ) e. Grp /\ X e. ( Base ` ( (mulGrp ` R ) ↾s U ) ) ) -> ( ( invg ` ( (mulGrp ` R ) ↾s U ) ) ` ( ( invg ` ( (mulGrp ` R ) ↾s U ) ) ` X ) ) = X )
13	9, 12	sylan 283	. . 3 |- ( ( R e. Ring /\ X e. ( Base ` ( (mulGrp ` R ) ↾s U ) ) ) -> ( ( invg ` ( (mulGrp ` R ) ↾s U ) ) ` ( ( invg ` ( (mulGrp ` R ) ↾s U ) ) ` X ) ) = X )
14	8, 13	sylbi 121	. 2 |- ( ( R e. Ring /\ X e. U ) -> ( ( invg ` ( (mulGrp ` R ) ↾s U ) ) ` ( ( invg ` ( (mulGrp ` R ) ↾s U ) ) ` X ) ) = X )
15		unitinvcl.2	. . . . . . 7 |- I = ( invr ` R )
16	15	a1i 9	. . . . . 6 |- ( R e. Ring -> I = ( invr ` R ) )
17		id 19	. . . . . 6 |- ( R e. Ring -> R e. Ring )
18	2, 4, 16, 17	invrfvald 14101	. . . . 5 |- ( R e. Ring -> I = ( invg ` ( (mulGrp ` R ) ↾s U ) ) )
19	18	fveq1d 5631	. . . . 5 |- ( R e. Ring -> ( I ` X ) = ( ( invg ` ( (mulGrp ` R ) ↾s U ) ) ` X ) )
20	18, 19	fveq12d 5636	. . . 4 |- ( R e. Ring -> ( I ` ( I ` X ) ) = ( ( invg ` ( (mulGrp ` R ) ↾s U ) ) ` ( ( invg ` ( (mulGrp ` R ) ↾s U ) ) ` X ) ) )
21	20	eqeq1d 2238	. . 3 |- ( R e. Ring -> ( ( I ` ( I ` X ) ) = X <-> ( ( invg ` ( (mulGrp ` R ) ↾s U ) ) ` ( ( invg ` ( (mulGrp ` R ) ↾s U ) ) ` X ) ) = X ) )
22	21	adantr 276	. 2 |- ( ( R e. Ring /\ X e. U ) -> ( ( I ` ( I ` X ) ) = X <-> ( ( invg ` ( (mulGrp ` R ) ↾s U ) ) ` ( ( invg ` ( (mulGrp ` R ) ↾s U ) ) ` X ) ) = X ) )
23	14, 22	mpbird 167	1 |- ( ( R e. Ring /\ X e. U ) -> ( I ` ( I ` X ) ) = X )

Syntax hints:   -> wi 4   /\ wa 104   <-> wb 105   = wceq 1395   e. wcel 2200   ` cfv 5318  (class class class)co 6007   Basecbs 13047   ↾_s cress 13048   Grpcgrp 13548   invgcminusg 13549  mulGrpcmgp 13898   Ringcrg 13974  Unitcui 14065   invrcinvr 14099

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 617  ax-in2 618  ax-io 714  ax-5 1493  ax-7 1494  ax-gen 1495  ax-ie1 1539  ax-ie2 1540  ax-8 1550  ax-10 1551  ax-11 1552  ax-i12 1553  ax-bndl 1555  ax-4 1556  ax-17 1572  ax-i9 1576  ax-ial 1580  ax-i5r 1581  ax-13 2202  ax-14 2203  ax-ext 2211  ax-coll 4199  ax-sep 4202  ax-nul 4210  ax-pow 4258  ax-pr 4293  ax-un 4524  ax-setind 4629  ax-cnex 8101  ax-resscn 8102  ax-1cn 8103  ax-1re 8104  ax-icn 8105  ax-addcl 8106  ax-addrcl 8107  ax-mulcl 8108  ax-addcom 8110  ax-addass 8112  ax-i2m1 8115  ax-0lt1 8116  ax-0id 8118  ax-rnegex 8119  ax-pre-ltirr 8122  ax-pre-lttrn 8124  ax-pre-ltadd 8126

This theorem depends on definitions:  df-bi 117  df-3an 1004  df-tru 1398  df-fal 1401  df-nf 1507  df-sb 1809  df-eu 2080  df-mo 2081  df-clab 2216  df-cleq 2222  df-clel 2225  df-nfc 2361  df-ne 2401  df-nel 2496  df-ral 2513  df-rex 2514  df-reu 2515  df-rmo 2516  df-rab 2517  df-v 2801  df-sbc 3029  df-csb 3125  df-dif 3199  df-un 3201  df-in 3203  df-ss 3210  df-nul 3492  df-pw 3651  df-sn 3672  df-pr 3673  df-op 3675  df-uni 3889  df-int 3924  df-iun 3967  df-br 4084  df-opab 4146  df-mpt 4147  df-id 4384  df-xp 4725  df-rel 4726  df-cnv 4727  df-co 4728  df-dm 4729  df-rn 4730  df-res 4731  df-ima 4732  df-iota 5278  df-fun 5320  df-fn 5321  df-f 5322  df-f1 5323  df-fo 5324  df-f1o 5325  df-fv 5326  df-riota 5960  df-ov 6010  df-oprab 6011  df-mpo 6012  df-tpos 6397  df-pnf 8194  df-mnf 8195  df-ltxr 8197  df-inn 9122  df-2 9180  df-3 9181  df-ndx 13050  df-slot 13051  df-base 13053  df-sets 13054  df-iress 13055  df-plusg 13138  df-mulr 13139  df-0g 13306  df-mgm 13404  df-sgrp 13450  df-mnd 13465  df-grp 13551  df-minusg 13552  df-cmn 13838  df-abl 13839  df-mgp 13899  df-ur 13938  df-srg 13942  df-ring 13976  df-oppr 14046  df-dvdsr 14067  df-unit 14068  df-invr 14100

This theorem is referenced by: (None)