Metamath Proof Explorer


Theorem imassc

Description: An image of a functor satisfies the subcategory subset relation. (Contributed by Zhi Wang, 7-Nov-2025)

Ref Expression
Hypotheses imasubc.s 𝑆 = ( 𝐹𝐴 )
imasubc.h 𝐻 = ( Hom ‘ 𝐷 )
imasubc.k 𝐾 = ( 𝑥𝑆 , 𝑦𝑆 𝑝 ∈ ( ( 𝐹 “ { 𝑥 } ) × ( 𝐹 “ { 𝑦 } ) ) ( ( 𝐺𝑝 ) “ ( 𝐻𝑝 ) ) )
imassc.f ( 𝜑𝐹 ( 𝐷 Func 𝐸 ) 𝐺 )
imassc.j 𝐽 = ( Homf𝐸 )
Assertion imassc ( 𝜑𝐾cat 𝐽 )

Proof

Step Hyp Ref Expression
1 imasubc.s 𝑆 = ( 𝐹𝐴 )
2 imasubc.h 𝐻 = ( Hom ‘ 𝐷 )
3 imasubc.k 𝐾 = ( 𝑥𝑆 , 𝑦𝑆 𝑝 ∈ ( ( 𝐹 “ { 𝑥 } ) × ( 𝐹 “ { 𝑦 } ) ) ( ( 𝐺𝑝 ) “ ( 𝐻𝑝 ) ) )
4 imassc.f ( 𝜑𝐹 ( 𝐷 Func 𝐸 ) 𝐺 )
5 imassc.j 𝐽 = ( Homf𝐸 )
6 eqid ( Base ‘ 𝐷 ) = ( Base ‘ 𝐷 )
7 eqid ( Base ‘ 𝐸 ) = ( Base ‘ 𝐸 )
8 6 7 4 funcf1 ( 𝜑𝐹 : ( Base ‘ 𝐷 ) ⟶ ( Base ‘ 𝐸 ) )
9 8 fimassd ( 𝜑 → ( 𝐹𝐴 ) ⊆ ( Base ‘ 𝐸 ) )
10 1 9 eqsstrid ( 𝜑𝑆 ⊆ ( Base ‘ 𝐸 ) )
11 eqid ( Hom ‘ 𝐸 ) = ( Hom ‘ 𝐸 )
12 4 ad2antrr ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → 𝐹 ( 𝐷 Func 𝐸 ) 𝐺 )
13 6 7 12 funcf1 ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → 𝐹 : ( Base ‘ 𝐷 ) ⟶ ( Base ‘ 𝐸 ) )
14 13 ffnd ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → 𝐹 Fn ( Base ‘ 𝐷 ) )
15 simprl ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) )
16 fniniseg ( 𝐹 Fn ( Base ‘ 𝐷 ) → ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ↔ ( 𝑚 ∈ ( Base ‘ 𝐷 ) ∧ ( 𝐹𝑚 ) = 𝑧 ) ) )
17 16 biimpa ( ( 𝐹 Fn ( Base ‘ 𝐷 ) ∧ 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ) → ( 𝑚 ∈ ( Base ‘ 𝐷 ) ∧ ( 𝐹𝑚 ) = 𝑧 ) )
18 14 15 17 syl2anc ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → ( 𝑚 ∈ ( Base ‘ 𝐷 ) ∧ ( 𝐹𝑚 ) = 𝑧 ) )
19 18 simpld ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → 𝑚 ∈ ( Base ‘ 𝐷 ) )
20 simprr ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) )
21 fniniseg ( 𝐹 Fn ( Base ‘ 𝐷 ) → ( 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ↔ ( 𝑛 ∈ ( Base ‘ 𝐷 ) ∧ ( 𝐹𝑛 ) = 𝑤 ) ) )
22 21 biimpa ( ( 𝐹 Fn ( Base ‘ 𝐷 ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) → ( 𝑛 ∈ ( Base ‘ 𝐷 ) ∧ ( 𝐹𝑛 ) = 𝑤 ) )
23 14 20 22 syl2anc ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → ( 𝑛 ∈ ( Base ‘ 𝐷 ) ∧ ( 𝐹𝑛 ) = 𝑤 ) )
24 23 simpld ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → 𝑛 ∈ ( Base ‘ 𝐷 ) )
25 6 2 11 12 19 24 funcf2 ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → ( 𝑚 𝐺 𝑛 ) : ( 𝑚 𝐻 𝑛 ) ⟶ ( ( 𝐹𝑚 ) ( Hom ‘ 𝐸 ) ( 𝐹𝑛 ) ) )
26 25 fimassd ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → ( ( 𝑚 𝐺 𝑛 ) “ ( 𝑚 𝐻 𝑛 ) ) ⊆ ( ( 𝐹𝑚 ) ( Hom ‘ 𝐸 ) ( 𝐹𝑛 ) ) )
27 18 simprd ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → ( 𝐹𝑚 ) = 𝑧 )
28 23 simprd ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → ( 𝐹𝑛 ) = 𝑤 )
29 27 28 oveq12d ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → ( ( 𝐹𝑚 ) ( Hom ‘ 𝐸 ) ( 𝐹𝑛 ) ) = ( 𝑧 ( Hom ‘ 𝐸 ) 𝑤 ) )
30 26 29 sseqtrd ( ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) ∧ ( 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∧ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ) ) → ( ( 𝑚 𝐺 𝑛 ) “ ( 𝑚 𝐻 𝑛 ) ) ⊆ ( 𝑧 ( Hom ‘ 𝐸 ) 𝑤 ) )
31 30 ralrimivva ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) → ∀ 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∀ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ( ( 𝑚 𝐺 𝑛 ) “ ( 𝑚 𝐻 𝑛 ) ) ⊆ ( 𝑧 ( Hom ‘ 𝐸 ) 𝑤 ) )
32 iunss ( 𝑝 ∈ ( ( 𝐹 “ { 𝑧 } ) × ( 𝐹 “ { 𝑤 } ) ) ( ( 𝐺𝑝 ) “ ( 𝐻𝑝 ) ) ⊆ ( 𝑧 ( Hom ‘ 𝐸 ) 𝑤 ) ↔ ∀ 𝑝 ∈ ( ( 𝐹 “ { 𝑧 } ) × ( 𝐹 “ { 𝑤 } ) ) ( ( 𝐺𝑝 ) “ ( 𝐻𝑝 ) ) ⊆ ( 𝑧 ( Hom ‘ 𝐸 ) 𝑤 ) )
33 fveq2 ( 𝑝 = ⟨ 𝑚 , 𝑛 ⟩ → ( 𝐺𝑝 ) = ( 𝐺 ‘ ⟨ 𝑚 , 𝑛 ⟩ ) )
34 df-ov ( 𝑚 𝐺 𝑛 ) = ( 𝐺 ‘ ⟨ 𝑚 , 𝑛 ⟩ )
35 33 34 eqtr4di ( 𝑝 = ⟨ 𝑚 , 𝑛 ⟩ → ( 𝐺𝑝 ) = ( 𝑚 𝐺 𝑛 ) )
36 fveq2 ( 𝑝 = ⟨ 𝑚 , 𝑛 ⟩ → ( 𝐻𝑝 ) = ( 𝐻 ‘ ⟨ 𝑚 , 𝑛 ⟩ ) )
37 df-ov ( 𝑚 𝐻 𝑛 ) = ( 𝐻 ‘ ⟨ 𝑚 , 𝑛 ⟩ )
38 36 37 eqtr4di ( 𝑝 = ⟨ 𝑚 , 𝑛 ⟩ → ( 𝐻𝑝 ) = ( 𝑚 𝐻 𝑛 ) )
39 35 38 imaeq12d ( 𝑝 = ⟨ 𝑚 , 𝑛 ⟩ → ( ( 𝐺𝑝 ) “ ( 𝐻𝑝 ) ) = ( ( 𝑚 𝐺 𝑛 ) “ ( 𝑚 𝐻 𝑛 ) ) )
40 39 sseq1d ( 𝑝 = ⟨ 𝑚 , 𝑛 ⟩ → ( ( ( 𝐺𝑝 ) “ ( 𝐻𝑝 ) ) ⊆ ( 𝑧 ( Hom ‘ 𝐸 ) 𝑤 ) ↔ ( ( 𝑚 𝐺 𝑛 ) “ ( 𝑚 𝐻 𝑛 ) ) ⊆ ( 𝑧 ( Hom ‘ 𝐸 ) 𝑤 ) ) )
41 40 ralxp ( ∀ 𝑝 ∈ ( ( 𝐹 “ { 𝑧 } ) × ( 𝐹 “ { 𝑤 } ) ) ( ( 𝐺𝑝 ) “ ( 𝐻𝑝 ) ) ⊆ ( 𝑧 ( Hom ‘ 𝐸 ) 𝑤 ) ↔ ∀ 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∀ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ( ( 𝑚 𝐺 𝑛 ) “ ( 𝑚 𝐻 𝑛 ) ) ⊆ ( 𝑧 ( Hom ‘ 𝐸 ) 𝑤 ) )
42 32 41 bitri ( 𝑝 ∈ ( ( 𝐹 “ { 𝑧 } ) × ( 𝐹 “ { 𝑤 } ) ) ( ( 𝐺𝑝 ) “ ( 𝐻𝑝 ) ) ⊆ ( 𝑧 ( Hom ‘ 𝐸 ) 𝑤 ) ↔ ∀ 𝑚 ∈ ( 𝐹 “ { 𝑧 } ) ∀ 𝑛 ∈ ( 𝐹 “ { 𝑤 } ) ( ( 𝑚 𝐺 𝑛 ) “ ( 𝑚 𝐻 𝑛 ) ) ⊆ ( 𝑧 ( Hom ‘ 𝐸 ) 𝑤 ) )
43 31 42 sylibr ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) → 𝑝 ∈ ( ( 𝐹 “ { 𝑧 } ) × ( 𝐹 “ { 𝑤 } ) ) ( ( 𝐺𝑝 ) “ ( 𝐻𝑝 ) ) ⊆ ( 𝑧 ( Hom ‘ 𝐸 ) 𝑤 ) )
44 relfunc Rel ( 𝐷 Func 𝐸 )
45 44 brrelex1i ( 𝐹 ( 𝐷 Func 𝐸 ) 𝐺𝐹 ∈ V )
46 4 45 syl ( 𝜑𝐹 ∈ V )
47 46 adantr ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) → 𝐹 ∈ V )
48 simprl ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) → 𝑧𝑆 )
49 simprr ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) → 𝑤𝑆 )
50 47 47 48 49 3 imasubclem3 ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) → ( 𝑧 𝐾 𝑤 ) = 𝑝 ∈ ( ( 𝐹 “ { 𝑧 } ) × ( 𝐹 “ { 𝑤 } ) ) ( ( 𝐺𝑝 ) “ ( 𝐻𝑝 ) ) )
51 10 adantr ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) → 𝑆 ⊆ ( Base ‘ 𝐸 ) )
52 51 48 sseldd ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) → 𝑧 ∈ ( Base ‘ 𝐸 ) )
53 51 49 sseldd ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) → 𝑤 ∈ ( Base ‘ 𝐸 ) )
54 5 7 11 52 53 homfval ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) → ( 𝑧 𝐽 𝑤 ) = ( 𝑧 ( Hom ‘ 𝐸 ) 𝑤 ) )
55 43 50 54 3sstr4d ( ( 𝜑 ∧ ( 𝑧𝑆𝑤𝑆 ) ) → ( 𝑧 𝐾 𝑤 ) ⊆ ( 𝑧 𝐽 𝑤 ) )
56 55 ralrimivva ( 𝜑 → ∀ 𝑧𝑆𝑤𝑆 ( 𝑧 𝐾 𝑤 ) ⊆ ( 𝑧 𝐽 𝑤 ) )
57 46 46 3 imasubclem2 ( 𝜑𝐾 Fn ( 𝑆 × 𝑆 ) )
58 5 7 homffn 𝐽 Fn ( ( Base ‘ 𝐸 ) × ( Base ‘ 𝐸 ) )
59 58 a1i ( 𝜑𝐽 Fn ( ( Base ‘ 𝐸 ) × ( Base ‘ 𝐸 ) ) )
60 fvexd ( 𝜑 → ( Base ‘ 𝐸 ) ∈ V )
61 57 59 60 isssc ( 𝜑 → ( 𝐾cat 𝐽 ↔ ( 𝑆 ⊆ ( Base ‘ 𝐸 ) ∧ ∀ 𝑧𝑆𝑤𝑆 ( 𝑧 𝐾 𝑤 ) ⊆ ( 𝑧 𝐽 𝑤 ) ) ) )
62 10 56 61 mpbir2and ( 𝜑𝐾cat 𝐽 )