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Theorem isghm 19183
Description: Property of being a homomorphism of groups. (Contributed by Stefan O'Rear, 31-Dec-2014.) (Proof shortened by SN, 5-Jun-2025.)
Hypotheses
Ref Expression
isghm.w 𝑋 = (Base‘𝑆)
isghm.x 𝑌 = (Base‘𝑇)
isghm.a + = (+g𝑆)
isghm.b = (+g𝑇)
Assertion
Ref Expression
isghm (𝐹 ∈ (𝑆 GrpHom 𝑇) ↔ ((𝑆 ∈ Grp ∧ 𝑇 ∈ Grp) ∧ (𝐹:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝐹‘(𝑢 + 𝑣)) = ((𝐹𝑢) (𝐹𝑣)))))
Distinct variable groups:   𝑣,𝑢,𝑆   𝑢,𝑇,𝑣   𝑢,𝑋,𝑣   𝑢, + ,𝑣   𝑢,𝑌,𝑣   𝑢, ,𝑣   𝑢,𝐹,𝑣

Proof of Theorem isghm
Dummy variables 𝑡 𝑠 𝑤 𝑓 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 df-ghm 19181 . . 3 GrpHom = (𝑠 ∈ Grp, 𝑡 ∈ Grp ↦ {𝑓[(Base‘𝑠) / 𝑤](𝑓:𝑤⟶(Base‘𝑡) ∧ ∀𝑢𝑤𝑣𝑤 (𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣)))})
21elmpocl 7662 . 2 (𝐹 ∈ (𝑆 GrpHom 𝑇) → (𝑆 ∈ Grp ∧ 𝑇 ∈ Grp))
3 fvex 6909 . . . . . . . 8 (Base‘𝑠) ∈ V
4 feq2 6705 . . . . . . . . 9 (𝑤 = (Base‘𝑠) → (𝑓:𝑤⟶(Base‘𝑡) ↔ 𝑓:(Base‘𝑠)⟶(Base‘𝑡)))
5 raleq 3311 . . . . . . . . . 10 (𝑤 = (Base‘𝑠) → (∀𝑣𝑤 (𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣)) ↔ ∀𝑣 ∈ (Base‘𝑠)(𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣))))
65raleqbi1dv 3322 . . . . . . . . 9 (𝑤 = (Base‘𝑠) → (∀𝑢𝑤𝑣𝑤 (𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣)) ↔ ∀𝑢 ∈ (Base‘𝑠)∀𝑣 ∈ (Base‘𝑠)(𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣))))
74, 6anbi12d 630 . . . . . . . 8 (𝑤 = (Base‘𝑠) → ((𝑓:𝑤⟶(Base‘𝑡) ∧ ∀𝑢𝑤𝑣𝑤 (𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣))) ↔ (𝑓:(Base‘𝑠)⟶(Base‘𝑡) ∧ ∀𝑢 ∈ (Base‘𝑠)∀𝑣 ∈ (Base‘𝑠)(𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣)))))
83, 7sbcie 3817 . . . . . . 7 ([(Base‘𝑠) / 𝑤](𝑓:𝑤⟶(Base‘𝑡) ∧ ∀𝑢𝑤𝑣𝑤 (𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣))) ↔ (𝑓:(Base‘𝑠)⟶(Base‘𝑡) ∧ ∀𝑢 ∈ (Base‘𝑠)∀𝑣 ∈ (Base‘𝑠)(𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣))))
9 fveq2 6896 . . . . . . . . . . 11 (𝑠 = 𝑆 → (Base‘𝑠) = (Base‘𝑆))
10 isghm.w . . . . . . . . . . 11 𝑋 = (Base‘𝑆)
119, 10eqtr4di 2783 . . . . . . . . . 10 (𝑠 = 𝑆 → (Base‘𝑠) = 𝑋)
1211adantr 479 . . . . . . . . 9 ((𝑠 = 𝑆𝑡 = 𝑇) → (Base‘𝑠) = 𝑋)
13 fveq2 6896 . . . . . . . . . . 11 (𝑡 = 𝑇 → (Base‘𝑡) = (Base‘𝑇))
14 isghm.x . . . . . . . . . . 11 𝑌 = (Base‘𝑇)
1513, 14eqtr4di 2783 . . . . . . . . . 10 (𝑡 = 𝑇 → (Base‘𝑡) = 𝑌)
1615adantl 480 . . . . . . . . 9 ((𝑠 = 𝑆𝑡 = 𝑇) → (Base‘𝑡) = 𝑌)
1712, 16feq23d 6718 . . . . . . . 8 ((𝑠 = 𝑆𝑡 = 𝑇) → (𝑓:(Base‘𝑠)⟶(Base‘𝑡) ↔ 𝑓:𝑋𝑌))
18 fveq2 6896 . . . . . . . . . . . . . 14 (𝑠 = 𝑆 → (+g𝑠) = (+g𝑆))
19 isghm.a . . . . . . . . . . . . . 14 + = (+g𝑆)
2018, 19eqtr4di 2783 . . . . . . . . . . . . 13 (𝑠 = 𝑆 → (+g𝑠) = + )
2120oveqd 7436 . . . . . . . . . . . 12 (𝑠 = 𝑆 → (𝑢(+g𝑠)𝑣) = (𝑢 + 𝑣))
2221fveq2d 6900 . . . . . . . . . . 11 (𝑠 = 𝑆 → (𝑓‘(𝑢(+g𝑠)𝑣)) = (𝑓‘(𝑢 + 𝑣)))
23 fveq2 6896 . . . . . . . . . . . . 13 (𝑡 = 𝑇 → (+g𝑡) = (+g𝑇))
24 isghm.b . . . . . . . . . . . . 13 = (+g𝑇)
2523, 24eqtr4di 2783 . . . . . . . . . . . 12 (𝑡 = 𝑇 → (+g𝑡) = )
2625oveqd 7436 . . . . . . . . . . 11 (𝑡 = 𝑇 → ((𝑓𝑢)(+g𝑡)(𝑓𝑣)) = ((𝑓𝑢) (𝑓𝑣)))
2722, 26eqeqan12d 2739 . . . . . . . . . 10 ((𝑠 = 𝑆𝑡 = 𝑇) → ((𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣)) ↔ (𝑓‘(𝑢 + 𝑣)) = ((𝑓𝑢) (𝑓𝑣))))
2812, 27raleqbidv 3329 . . . . . . . . 9 ((𝑠 = 𝑆𝑡 = 𝑇) → (∀𝑣 ∈ (Base‘𝑠)(𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣)) ↔ ∀𝑣𝑋 (𝑓‘(𝑢 + 𝑣)) = ((𝑓𝑢) (𝑓𝑣))))
2912, 28raleqbidv 3329 . . . . . . . 8 ((𝑠 = 𝑆𝑡 = 𝑇) → (∀𝑢 ∈ (Base‘𝑠)∀𝑣 ∈ (Base‘𝑠)(𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣)) ↔ ∀𝑢𝑋𝑣𝑋 (𝑓‘(𝑢 + 𝑣)) = ((𝑓𝑢) (𝑓𝑣))))
3017, 29anbi12d 630 . . . . . . 7 ((𝑠 = 𝑆𝑡 = 𝑇) → ((𝑓:(Base‘𝑠)⟶(Base‘𝑡) ∧ ∀𝑢 ∈ (Base‘𝑠)∀𝑣 ∈ (Base‘𝑠)(𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣))) ↔ (𝑓:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝑓‘(𝑢 + 𝑣)) = ((𝑓𝑢) (𝑓𝑣)))))
318, 30bitrid 282 . . . . . 6 ((𝑠 = 𝑆𝑡 = 𝑇) → ([(Base‘𝑠) / 𝑤](𝑓:𝑤⟶(Base‘𝑡) ∧ ∀𝑢𝑤𝑣𝑤 (𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣))) ↔ (𝑓:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝑓‘(𝑢 + 𝑣)) = ((𝑓𝑢) (𝑓𝑣)))))
3231abbidv 2794 . . . . 5 ((𝑠 = 𝑆𝑡 = 𝑇) → {𝑓[(Base‘𝑠) / 𝑤](𝑓:𝑤⟶(Base‘𝑡) ∧ ∀𝑢𝑤𝑣𝑤 (𝑓‘(𝑢(+g𝑠)𝑣)) = ((𝑓𝑢)(+g𝑡)(𝑓𝑣)))} = {𝑓 ∣ (𝑓:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝑓‘(𝑢 + 𝑣)) = ((𝑓𝑢) (𝑓𝑣)))})
3314fvexi 6910 . . . . . . 7 𝑌 ∈ V
34 fsetex 8875 . . . . . . 7 (𝑌 ∈ V → {𝑓𝑓:𝑋𝑌} ∈ V)
3533, 34ax-mp 5 . . . . . 6 {𝑓𝑓:𝑋𝑌} ∈ V
36 abanssl 4300 . . . . . 6 {𝑓 ∣ (𝑓:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝑓‘(𝑢 + 𝑣)) = ((𝑓𝑢) (𝑓𝑣)))} ⊆ {𝑓𝑓:𝑋𝑌}
3735, 36ssexi 5323 . . . . 5 {𝑓 ∣ (𝑓:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝑓‘(𝑢 + 𝑣)) = ((𝑓𝑢) (𝑓𝑣)))} ∈ V
3832, 1, 37ovmpoa 7576 . . . 4 ((𝑆 ∈ Grp ∧ 𝑇 ∈ Grp) → (𝑆 GrpHom 𝑇) = {𝑓 ∣ (𝑓:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝑓‘(𝑢 + 𝑣)) = ((𝑓𝑢) (𝑓𝑣)))})
3938eleq2d 2811 . . 3 ((𝑆 ∈ Grp ∧ 𝑇 ∈ Grp) → (𝐹 ∈ (𝑆 GrpHom 𝑇) ↔ 𝐹 ∈ {𝑓 ∣ (𝑓:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝑓‘(𝑢 + 𝑣)) = ((𝑓𝑢) (𝑓𝑣)))}))
4010fvexi 6910 . . . . . 6 𝑋 ∈ V
41 fex2 7942 . . . . . 6 ((𝐹:𝑋𝑌𝑋 ∈ V ∧ 𝑌 ∈ V) → 𝐹 ∈ V)
4240, 33, 41mp3an23 1449 . . . . 5 (𝐹:𝑋𝑌𝐹 ∈ V)
4342adantr 479 . . . 4 ((𝐹:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝐹‘(𝑢 + 𝑣)) = ((𝐹𝑢) (𝐹𝑣))) → 𝐹 ∈ V)
44 feq1 6704 . . . . 5 (𝑓 = 𝐹 → (𝑓:𝑋𝑌𝐹:𝑋𝑌))
45 fveq1 6895 . . . . . . 7 (𝑓 = 𝐹 → (𝑓‘(𝑢 + 𝑣)) = (𝐹‘(𝑢 + 𝑣)))
46 fveq1 6895 . . . . . . . 8 (𝑓 = 𝐹 → (𝑓𝑢) = (𝐹𝑢))
47 fveq1 6895 . . . . . . . 8 (𝑓 = 𝐹 → (𝑓𝑣) = (𝐹𝑣))
4846, 47oveq12d 7437 . . . . . . 7 (𝑓 = 𝐹 → ((𝑓𝑢) (𝑓𝑣)) = ((𝐹𝑢) (𝐹𝑣)))
4945, 48eqeq12d 2741 . . . . . 6 (𝑓 = 𝐹 → ((𝑓‘(𝑢 + 𝑣)) = ((𝑓𝑢) (𝑓𝑣)) ↔ (𝐹‘(𝑢 + 𝑣)) = ((𝐹𝑢) (𝐹𝑣))))
50492ralbidv 3208 . . . . 5 (𝑓 = 𝐹 → (∀𝑢𝑋𝑣𝑋 (𝑓‘(𝑢 + 𝑣)) = ((𝑓𝑢) (𝑓𝑣)) ↔ ∀𝑢𝑋𝑣𝑋 (𝐹‘(𝑢 + 𝑣)) = ((𝐹𝑢) (𝐹𝑣))))
5144, 50anbi12d 630 . . . 4 (𝑓 = 𝐹 → ((𝑓:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝑓‘(𝑢 + 𝑣)) = ((𝑓𝑢) (𝑓𝑣))) ↔ (𝐹:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝐹‘(𝑢 + 𝑣)) = ((𝐹𝑢) (𝐹𝑣)))))
5243, 51elab3 3672 . . 3 (𝐹 ∈ {𝑓 ∣ (𝑓:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝑓‘(𝑢 + 𝑣)) = ((𝑓𝑢) (𝑓𝑣)))} ↔ (𝐹:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝐹‘(𝑢 + 𝑣)) = ((𝐹𝑢) (𝐹𝑣))))
5339, 52bitrdi 286 . 2 ((𝑆 ∈ Grp ∧ 𝑇 ∈ Grp) → (𝐹 ∈ (𝑆 GrpHom 𝑇) ↔ (𝐹:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝐹‘(𝑢 + 𝑣)) = ((𝐹𝑢) (𝐹𝑣)))))
542, 53biadanii 820 1 (𝐹 ∈ (𝑆 GrpHom 𝑇) ↔ ((𝑆 ∈ Grp ∧ 𝑇 ∈ Grp) ∧ (𝐹:𝑋𝑌 ∧ ∀𝑢𝑋𝑣𝑋 (𝐹‘(𝑢 + 𝑣)) = ((𝐹𝑢) (𝐹𝑣)))))
Colors of variables: wff setvar class
Syntax hints:  wb 205  wa 394   = wceq 1533  wcel 2098  {cab 2702  wral 3050  Vcvv 3461  [wsbc 3773  wf 6545  cfv 6549  (class class class)co 7419  Basecbs 17188  +gcplusg 17241  Grpcgrp 18903   GrpHom cghm 19180
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1789  ax-4 1803  ax-5 1905  ax-6 1963  ax-7 2003  ax-8 2100  ax-9 2108  ax-10 2129  ax-11 2146  ax-12 2166  ax-ext 2696  ax-sep 5300  ax-nul 5307  ax-pow 5365  ax-pr 5429  ax-un 7741
This theorem depends on definitions:  df-bi 206  df-an 395  df-or 846  df-3an 1086  df-tru 1536  df-fal 1546  df-ex 1774  df-nf 1778  df-sb 2060  df-mo 2528  df-eu 2557  df-clab 2703  df-cleq 2717  df-clel 2802  df-nfc 2877  df-ne 2930  df-ral 3051  df-rex 3060  df-rab 3419  df-v 3463  df-sbc 3774  df-csb 3890  df-dif 3947  df-un 3949  df-in 3951  df-ss 3961  df-nul 4323  df-if 4531  df-pw 4606  df-sn 4631  df-pr 4633  df-op 4637  df-uni 4910  df-iun 4999  df-br 5150  df-opab 5212  df-mpt 5233  df-id 5576  df-xp 5684  df-rel 5685  df-cnv 5686  df-co 5687  df-dm 5688  df-rn 5689  df-res 5690  df-ima 5691  df-iota 6501  df-fun 6551  df-fn 6552  df-f 6553  df-fv 6557  df-ov 7422  df-oprab 7423  df-mpo 7424  df-1st 7994  df-2nd 7995  df-map 8847  df-ghm 19181
This theorem is referenced by:  isghm3  19185  ghmgrp1  19186  ghmgrp2  19187  ghmf  19188  ghmlin  19189  isghmd  19193  idghm  19199  ghmf1o  19216  isrnghm  20397  rhmopp  20465  islmhm2  20940  expghm  21423  mulgghm2  21424  pi1xfr  25031  pi1coghm  25037  zringfrac  33371
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