Theorem imasubc3 50411

Description: An image of a functor injective on objects is a subcategory. Remark 4.2(3) of [Adamek] p. 48. (Contributed by Zhi Wang, 7-Nov-2025.)

Hypotheses

Ref	Expression
imasubc.s	⊢ 𝑆 = (𝐹 “ 𝐴)
imasubc.h	⊢ 𝐻 = (Hom ‘𝐷)
imasubc.k	⊢ 𝐾 = (𝑥 ∈ 𝑆, 𝑦 ∈ 𝑆 ↦ ∪ 𝑝 ∈ ((◡𝐹 “ {𝑥}) × (◡𝐹 “ {𝑦}))((𝐺‘𝑝) “ (𝐻‘𝑝)))
imassc.f	⊢ (𝜑 → 𝐹(𝐷 Func 𝐸)𝐺)
imasubc3.f	⊢ (𝜑 → Fun ◡𝐹)

Assertion

Ref	Expression
imasubc3	⊢ (𝜑 → 𝐾 ∈ (Subcat‘𝐸))

Distinct variable groups:   𝐹,𝑝,𝑥,𝑦   𝐺,𝑝,𝑥,𝑦   𝐻,𝑝,𝑥,𝑦   𝑥,𝑆,𝑦   𝐸,𝑝   𝜑,𝑥,𝑦

Allowed substitution hints:   𝜑(𝑝)   𝐴(𝑥, 𝑦, 𝑝)   𝐷(𝑥, 𝑦, 𝑝)   𝑆(𝑝)   𝐸(𝑥, 𝑦)   𝐾(𝑥, 𝑦, 𝑝)

Proof of Theorem imasubc3

Dummy variables 𝑎 𝑏 𝑐 𝑓 𝑔 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		imasubc.s	. . 3 ⊢ 𝑆 = (𝐹 “ 𝐴)
2		imasubc.h	. . 3 ⊢ 𝐻 = (Hom ‘𝐷)
3		imasubc.k	. . 3 ⊢ 𝐾 = (𝑥 ∈ 𝑆, 𝑦 ∈ 𝑆 ↦ ∪ 𝑝 ∈ ((◡𝐹 “ {𝑥}) × (◡𝐹 “ {𝑦}))((𝐺‘𝑝) “ (𝐻‘𝑝)))
4		imassc.f	. . 3 ⊢ (𝜑 → 𝐹(𝐷 Func 𝐸)𝐺)
5		eqid 2763	. . 3 ⊢ (Homf ‘𝐸) = (Homf ‘𝐸)
6	1, 2, 3, 4, 5	imassc 50408	. 2 ⊢ (𝜑 → 𝐾 ⊆cat (Homf ‘𝐸))
7	4	adantr 486	. . . . 5 ⊢ ((𝜑 ∧ 𝑎 ∈ 𝑆) → 𝐹(𝐷 Func 𝐸)𝐺)
8		eqid 2763	. . . . 5 ⊢ (Id‘𝐸) = (Id‘𝐸)
9		simpr 490	. . . . 5 ⊢ ((𝜑 ∧ 𝑎 ∈ 𝑆) → 𝑎 ∈ 𝑆)
10	1, 2, 3, 7, 8, 9	imaid 50409	. . . 4 ⊢ ((𝜑 ∧ 𝑎 ∈ 𝑆) → ((Id‘𝐸)‘𝑎) ∈ (𝑎𝐾𝑎))
11	4	ad3antrrr 743	. . . . . . 7 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐾𝑏) ∧ 𝑔 ∈ (𝑏𝐾𝑐))) → 𝐹(𝐷 Func 𝐸)𝐺)
12		eqid 2763	. . . . . . 7 ⊢ (Base‘𝐷) = (Base‘𝐷)
13		eqid 2763	. . . . . . 7 ⊢ (Base‘𝐸) = (Base‘𝐸)
14		eqid 2763	. . . . . . 7 ⊢ (comp‘𝐸) = (comp‘𝐸)
15	12, 13, 4	funcf1 18053	. . . . . . . . 9 ⊢ (𝜑 → 𝐹:(Base‘𝐷)⟶(Base‘𝐸))
16		imasubc3.f	. . . . . . . . 9 ⊢ (𝜑 → Fun ◡𝐹)
17		df-f1 6551	. . . . . . . . 9 ⊢ (𝐹:(Base‘𝐷)–1-1→(Base‘𝐸) ↔ (𝐹:(Base‘𝐷)⟶(Base‘𝐸) ∧ Fun ◡𝐹))
18	15, 16, 17	sylanbrc 595	. . . . . . . 8 ⊢ (𝜑 → 𝐹:(Base‘𝐷)–1-1→(Base‘𝐸))
19	18	ad3antrrr 743	. . . . . . 7 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐾𝑏) ∧ 𝑔 ∈ (𝑏𝐾𝑐))) → 𝐹:(Base‘𝐷)–1-1→(Base‘𝐸))
20		simpllr 788	. . . . . . 7 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐾𝑏) ∧ 𝑔 ∈ (𝑏𝐾𝑐))) → 𝑎 ∈ 𝑆)
21		simplrl 789	. . . . . . 7 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐾𝑏) ∧ 𝑔 ∈ (𝑏𝐾𝑐))) → 𝑏 ∈ 𝑆)
22		simplrr 790	. . . . . . 7 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐾𝑏) ∧ 𝑔 ∈ (𝑏𝐾𝑐))) → 𝑐 ∈ 𝑆)
23		simprl 783	. . . . . . 7 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐾𝑏) ∧ 𝑔 ∈ (𝑏𝐾𝑐))) → 𝑓 ∈ (𝑎𝐾𝑏))
24		simprr 785	. . . . . . 7 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐾𝑏) ∧ 𝑔 ∈ (𝑏𝐾𝑐))) → 𝑔 ∈ (𝑏𝐾𝑐))
25	1, 2, 3, 11, 12, 13, 14, 19, 20, 21, 22, 23, 24	imaf1co 50410	. . . . . 6 ⊢ ((((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) ∧ (𝑓 ∈ (𝑎𝐾𝑏) ∧ 𝑔 ∈ (𝑏𝐾𝑐))) → (𝑔(⟨𝑎, 𝑏⟩(comp‘𝐸)𝑐)𝑓) ∈ (𝑎𝐾𝑐))
26	25	ralrimivva 3208	. . . . 5 ⊢ (((𝜑 ∧ 𝑎 ∈ 𝑆) ∧ (𝑏 ∈ 𝑆 ∧ 𝑐 ∈ 𝑆)) → ∀𝑓 ∈ (𝑎𝐾𝑏)∀𝑔 ∈ (𝑏𝐾𝑐)(𝑔(⟨𝑎, 𝑏⟩(comp‘𝐸)𝑐)𝑓) ∈ (𝑎𝐾𝑐))
27	26	ralrimivva 3208	. . . 4 ⊢ ((𝜑 ∧ 𝑎 ∈ 𝑆) → ∀𝑏 ∈ 𝑆 ∀𝑐 ∈ 𝑆 ∀𝑓 ∈ (𝑎𝐾𝑏)∀𝑔 ∈ (𝑏𝐾𝑐)(𝑔(⟨𝑎, 𝑏⟩(comp‘𝐸)𝑐)𝑓) ∈ (𝑎𝐾𝑐))
28	10, 27	jca 521	. . 3 ⊢ ((𝜑 ∧ 𝑎 ∈ 𝑆) → (((Id‘𝐸)‘𝑎) ∈ (𝑎𝐾𝑎) ∧ ∀𝑏 ∈ 𝑆 ∀𝑐 ∈ 𝑆 ∀𝑓 ∈ (𝑎𝐾𝑏)∀𝑔 ∈ (𝑏𝐾𝑐)(𝑔(⟨𝑎, 𝑏⟩(comp‘𝐸)𝑐)𝑓) ∈ (𝑎𝐾𝑐)))
29	28	ralrimiva 3157	. 2 ⊢ (𝜑 → ∀𝑎 ∈ 𝑆 (((Id‘𝐸)‘𝑎) ∈ (𝑎𝐾𝑎) ∧ ∀𝑏 ∈ 𝑆 ∀𝑐 ∈ 𝑆 ∀𝑓 ∈ (𝑎𝐾𝑏)∀𝑔 ∈ (𝑏𝐾𝑐)(𝑔(⟨𝑎, 𝑏⟩(comp‘𝐸)𝑐)𝑓) ∈ (𝑎𝐾𝑐)))
30	4	funcrcl3 50333	. . 3 ⊢ (𝜑 → 𝐸 ∈ Cat)
31		relfunc 18049	. . . . . 6 ⊢ Rel (𝐷 Func 𝐸)
32	31	brrelex1i 5710	. . . . 5 ⊢ (𝐹(𝐷 Func 𝐸)𝐺 → 𝐹 ∈ V)
33	4, 32	syl 18	. . . 4 ⊢ (𝜑 → 𝐹 ∈ V)
34	33, 33, 3	imasubclem2 50360	. . 3 ⊢ (𝜑 → 𝐾 Fn (𝑆 × 𝑆))
35	5, 8, 14, 30, 34	issubc2 18023	. 2 ⊢ (𝜑 → (𝐾 ∈ (Subcat‘𝐸) ↔ (𝐾 ⊆cat (Homf ‘𝐸) ∧ ∀𝑎 ∈ 𝑆 (((Id‘𝐸)‘𝑎) ∈ (𝑎𝐾𝑎) ∧ ∀𝑏 ∈ 𝑆 ∀𝑐 ∈ 𝑆 ∀𝑓 ∈ (𝑎𝐾𝑏)∀𝑔 ∈ (𝑏𝐾𝑐)(𝑔(⟨𝑎, 𝑏⟩(comp‘𝐸)𝑐)𝑓) ∈ (𝑎𝐾𝑐)))))
36	6, 29, 35	mpbir2and 726	1 ⊢ (𝜑 → 𝐾 ∈ (Subcat‘𝐸))

This proof depends on syntax axioms:   → wi 4   ∧ wa 401   = wceq 1569   ∈ wcel 2146  ∀wral 3079  Vcvv 3453  {csn 4587  ⟨cop 4837  ∪ ciun 4953   class class class wbr 5105   × cxp 5652  ^◡ccnv 5653   “ cima 5657  Fun wfun 6540  ⟶wf 6542  –1-1→wf1 6543  ‘cfv 6546  (class class class)co 7427   ∈ cmpo 7429  Basecbs 17399  Hom chom 17451  compcco 17452  Idccid 17851  Hom_f chomf 17852   ⊆_cat cssc 17994  Subcatcsubc 17996   Func cfunc 18041

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1827  ax-4 1841  ax-5 1944  ax-6 2001  ax-7 2042  ax-8 2148  ax-9 2156  ax-10 2179  ax-11 2196  ax-12 2215  ax-ext 2735  ax-rep 5234  ax-sep 5251  ax-nul 5262  ax-pow 5330  ax-pr 5394  ax-un 7758

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3an 1105  df-tru 1572  df-fal 1582  df-ex 1812  df-nf 1816  df-sb 2101  df-mo 2567  df-eu 2597  df-clab 2742  df-cleq 2755  df-clel 2838  df-nfc 2912  df-ne 2959  df-ral 3080  df-rex 3090  df-rmo 3368  df-reu 3369  df-rab 3416  df-v 3455  df-sbc 3742  df-csb 3851  df-ss 3900  df-dif 4049  df-in 4093  df-un 4153  df-nul 4281  df-if 4485  df-pw 4561  df-sn 4588  df-pr 4590  df-op 4838  df-uni 4870  df-iun 4955  df-br 5106  df-opab 5170  df-mpt 5189  df-id 5549  df-xp 5660  df-rel 5661  df-cnv 5662  df-co 5663  df-dm 5664  df-rn 5665  df-res 5666  df-ima 5667  df-iota 6500  df-fun 6548  df-fn 6549  df-f 6550  df-f1 6551  df-fo 6552  df-f1o 6553  df-fv 6554  df-riota 7384  df-ov 7430  df-oprab 7431  df-mpo 7432  df-1st 8008  df-2nd 8009  df-map 8860  df-pm 8861  df-ixp 8937  df-cat 17854  df-cid 17855  df-homf 17856  df-ssc 17997  df-subc 17999  df-func 18045

This theorem is used by:  idsubc  50415