HomeHome Metamath Proof Explorer < Previous   Next >
Related theorems
Unicode version

Theorem grpideu 10098
Description: The left identity element of a group is unique. Lemma 2.2.1(a) of [Herstein] p. 55.
Hypotheses
Ref Expression
grplem1.b |- B = (Base` G)
grplem1.p |- P = ( +g ` G)
Assertion
Ref Expression
grpideu |- (G e. Grp -> E!u e. B A.x e. B (uPx) = x)
Distinct variable groups:   x,u,B   u,P,x   u,G,x

Proof of Theorem grpideu
StepHypRef Expression
1 grplem1.b . . . 4 |- B = (Base` G)
2 grplem1.p . . . 4 |- P = ( +g ` G)
31, 2grpidinv 10097 . . 3 |- (G e. Grp -> E.u e. B A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u)))
4 simpll 744 . . . . . . . . 9 |- ((((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u)) -> (uPz) = z)
54ralimi 2234 . . . . . . . 8 |- (A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u)) -> A.z e. B (uPz) = z)
6 oveq2 4930 . . . . . . . . . 10 |- (z = x -> (uPz) = (uPx))
7 id 19 . . . . . . . . . 10 |- (z = x -> z = x)
86, 7eqeq12d 1974 . . . . . . . . 9 |- (z = x -> ((uPz) = z <-> (uPx) = x))
98cbvralv 2349 . . . . . . . 8 |- (A.z e. B (uPz) = z <-> A.x e. B (uPx) = x)
105, 9sylib 201 . . . . . . 7 |- (A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u)) -> A.x e. B (uPx) = x)
1110adantl 475 . . . . . 6 |- (((G e. Grp /\ u e. B) /\ A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u))) -> A.x e. B (uPx) = x)
1210ad2antlr 737 . . . . . . . 8 |- ((((G e. Grp /\ u e. B) /\ A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u))) /\ w e. B) -> A.x e. B (uPx) = x)
13 simpr 469 . . . . . . . . . . . . . . . 16 |- ((((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u)) -> E.y e. B ((yPz) = u /\ (zPy) = u))
1413ralimi 2234 . . . . . . . . . . . . . . 15 |- (A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u)) -> A.z e. B E.y e. B ((yPz) = u /\ (zPy) = u))
15 oveq2 4930 . . . . . . . . . . . . . . . . . . . 20 |- (z = w -> (yPz) = (yPw))
1615eqeq1d 1968 . . . . . . . . . . . . . . . . . . 19 |- (z = w -> ((yPz) = u <-> (yPw) = u))
17 oveq1 4929 . . . . . . . . . . . . . . . . . . . 20 |- (z = w -> (zPy) = (wPy))
1817eqeq1d 1968 . . . . . . . . . . . . . . . . . . 19 |- (z = w -> ((zPy) = u <-> (wPy) = u))
1916, 18anbi12d 720 . . . . . . . . . . . . . . . . . 18 |- (z = w -> (((yPz) = u /\ (zPy) = u) <-> ((yPw) = u /\ (wPy) = u)))
2019rexbidv 2188 . . . . . . . . . . . . . . . . 17 |- (z = w -> (E.y e. B ((yPz) = u /\ (zPy) = u) <-> E.y e. B ((yPw) = u /\ (wPy) = u)))
2120rcla4va 2449 . . . . . . . . . . . . . . . 16 |- ((w e. B /\ A.z e. B E.y e. B ((yPz) = u /\ (zPy) = u)) -> E.y e. B ((yPw) = u /\ (wPy) = u))
2221adantll 723 . . . . . . . . . . . . . . 15 |- (((G e. Grp /\ w e. B) /\ A.z e. B E.y e. B ((yPz) = u /\ (zPy) = u)) -> E.y e. B ((yPw) = u /\ (wPy) = u))
2314, 22sylan2 483 . . . . . . . . . . . . . 14 |- (((G e. Grp /\ w e. B) /\ A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u))) -> E.y e. B ((yPw) = u /\ (wPy) = u))
241, 2grpidinvlem4 10096 . . . . . . . . . . . . . 14 |- (((G e. Grp /\ w e. B) /\ E.y e. B ((yPw) = u /\ (wPy) = u)) -> (wPu) = (uPw))
2523, 24syldan 479 . . . . . . . . . . . . 13 |- (((G e. Grp /\ w e. B) /\ A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u))) -> (wPu) = (uPw))
2625an32s 778 . . . . . . . . . . . 12 |- (((G e. Grp /\ A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u))) /\ w e. B) -> (wPu) = (uPw))
2726adantllr 728 . . . . . . . . . . 11 |- ((((G e. Grp /\ u e. B) /\ A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u))) /\ w e. B) -> (wPu) = (uPw))
2827adantr 474 . . . . . . . . . 10 |- (((((G e. Grp /\ u e. B) /\ A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u))) /\ w e. B) /\ (A.x e. B (uPx) = x /\ A.x e. B (wPx) = x)) -> (wPu) = (uPw))
29 oveq2 4930 . . . . . . . . . . . . . . 15 |- (x = u -> (wPx) = (wPu))
30 id 19 . . . . . . . . . . . . . . 15 |- (x = u -> x = u)
3129, 30eqeq12d 1974 . . . . . . . . . . . . . 14 |- (x = u -> ((wPx) = x <-> (wPu) = u))
3231rcla4va 2449 . . . . . . . . . . . . 13 |- ((u e. B /\ A.x e. B (wPx) = x) -> (wPu) = u)
3332adantll 723 . . . . . . . . . . . 12 |- (((G e. Grp /\ u e. B) /\ A.x e. B (wPx) = x) -> (wPu) = u)
3433ad2ant2rl 743 . . . . . . . . . . 11 |- ((((G e. Grp /\ u e. B) /\ w e. B) /\ (A.x e. B (uPx) = x /\ A.x e. B (wPx) = x)) -> (wPu) = u)
3534adantllr 728 . . . . . . . . . 10 |- (((((G e. Grp /\ u e. B) /\ A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u))) /\ w e. B) /\ (A.x e. B (uPx) = x /\ A.x e. B (wPx) = x)) -> (wPu) = u)
36 oveq2 4930 . . . . . . . . . . . . 13 |- (x = w -> (uPx) = (uPw))
37 id 19 . . . . . . . . . . . . 13 |- (x = w -> x = w)
3836, 37eqeq12d 1974 . . . . . . . . . . . 12 |- (x = w -> ((uPx) = x <-> (uPw) = w))
3938rcla4va 2449 . . . . . . . . . . 11 |- ((w e. B /\ A.x e. B (uPx) = x) -> (uPw) = w)
4039ad2ant2lr 742 . . . . . . . . . 10 |- (((((G e. Grp /\ u e. B) /\ A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u))) /\ w e. B) /\ (A.x e. B (uPx) = x /\ A.x e. B (wPx) = x)) -> (uPw) = w)
4128, 35, 403eqtr3d 2000 . . . . . . . . 9 |- (((((G e. Grp /\ u e. B) /\ A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u))) /\ w e. B) /\ (A.x e. B (uPx) = x /\ A.x e. B (wPx) = x)) -> u = w)
4241ex 448 . . . . . . . 8 |- ((((G e. Grp /\ u e. B) /\ A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u))) /\ w e. B) -> ((A.x e. B (uPx) = x /\ A.x e. B (wPx) = x) -> u = w))
4312, 42mpand 682 . . . . . . 7 |- ((((G e. Grp /\ u e. B) /\ A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u))) /\ w e. B) -> (A.x e. B (wPx) = x -> u = w))
4443ralrimiva 2242 . . . . . 6 |- (((G e. Grp /\ u e. B) /\ A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u))) -> A.w e. B (A.x e. B (wPx) = x -> u = w))
4511, 44jca 541 . . . . 5 |- (((G e. Grp /\ u e. B) /\ A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u))) -> (A.x e. B (uPx) = x /\ A.w e. B (A.x e. B (wPx) = x -> u = w)))
4645ex 448 . . . 4 |- ((G e. Grp /\ u e. B) -> (A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u)) -> (A.x e. B (uPx) = x /\ A.w e. B (A.x e. B (wPx) = x -> u = w))))
4746reximdva 2271 . . 3 |- (G e. Grp -> (E.u e. B A.z e. B (((uPz) = z /\ (zPu) = z) /\ E.y e. B ((yPz) = u /\ (zPy) = u)) -> E.u e. B (A.x e. B (uPx) = x /\ A.w e. B (A.x e. B (wPx) = x -> u = w))))
483, 47mpd 13 . 2 |- (G e. Grp -> E.u e. B (A.x e. B (uPx) = x /\ A.w e. B (A.x e. B (wPx) = x -> u = w)))
49 oveq1 4929 . . . . 5 |- (u = w -> (uPx) = (wPx))
5049eqeq1d 1968 . . . 4 |- (u = w -> ((uPx) = x <-> (wPx) = x))
5150ralbidv 2187 . . 3 |- (u = w -> (A.x e. B (uPx) = x <-> A.x e. B (wPx) = x))
5251reu8 2528 . 2 |- (E!u e. B A.x e. B (uPx) = x <-> E.u e. B (A.x e. B (uPx) = x /\ A.w e. B (A.x e. B (wPx) = x -> u = w)))
5348, 52sylibr 221 1 |- (G e. Grp -> E!u e. B A.x e. B (uPx) = x)
Colors of variables: wff set class
Syntax hints:   -> wi 4   /\ wa 382   = wceq 1457   e. wcel 1459  A.wral 2169  E.wrex 2170  E!wreu 2171  ` cfv 4012  (class class class)co 4924  Basecbs 9856   +g cplusg 10064  Grpcgrp 10065
This theorem is referenced by:  grpidcl 10107  grpidinv2 10108  isgrpid 10111
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-5 1376  ax-6 1377  ax-7 1378  ax-gen 1379  ax-8 1461  ax-10 1462  ax-11 1463  ax-12 1464  ax-13 1465  ax-14 1466  ax-17 1473  ax-9 1488  ax-4 1494  ax-16 1671  ax-ext 1942  ax-sep 3472  ax-nul 3481  ax-pr 3541  ax-un 3811
This theorem depends on definitions:  df-bi 190  df-or 383  df-an 384  df-3an 948  df-ex 1381  df-sb 1633  df-eu 1860  df-mo 1861  df-clab 1948  df-cleq 1953  df-clel 1956  df-ne 2080  df-ral 2173  df-rex 2174  df-reu 2175  df-v 2367  df-dif 2665  df-un 2667  df-in 2669  df-ss 2671  df-nul 2927  df-sn 3099  df-pr 3100  df-op 3103  df-uni 3232  df-br 3377  df-opab 3431  df-xp 4014  df-cnv 4016  df-dm 4018  df-rn 4019  df-res 4020  df-ima 4021  df-fv 4028  df-ov 4926  df-grp 10071
Copyright terms: Public domain