Theorem sscrel 17272

Description: The subcategory subset relation is a relation. (Contributed by Mario Carneiro, 6-Jan-2017.)

Assertion

Ref	Expression
sscrel	⊢ Rel ⊆cat

Proof of Theorem sscrel

Dummy variables ℎ 𝑗 𝑠 𝑡 𝑥 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		df-ssc 17269	. 2 ⊢ ⊆cat = {⟨ℎ, 𝑗⟩ ∣ ∃𝑡(𝑗 Fn (𝑡 × 𝑡) ∧ ∃𝑠 ∈ 𝒫 𝑡ℎ ∈ X𝑥 ∈ (𝑠 × 𝑠)𝒫 (𝑗‘𝑥))}
2	1	relopabiv 5675	1 ⊢ Rel ⊆cat

Syntax hints:   ∧ wa 399  ∃wex 1787   ∈ wcel 2112  ∃wrex 3052  𝒫 cpw 4499   × cxp 5534  Rel wrel 5541   Fn wfn 6353  ‘cfv 6358  Xcixp 8556   ⊆_cat cssc 17266

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1803  ax-4 1817  ax-5 1918  ax-6 1976  ax-7 2018  ax-8 2114  ax-9 2122  ax-ext 2708

This theorem depends on definitions:  df-bi 210  df-an 400  df-tru 1546  df-ex 1788  df-sb 2073  df-clab 2715  df-cleq 2728  df-clel 2809  df-v 3400  df-in 3860  df-ss 3870  df-opab 5102  df-xp 5542  df-rel 5543  df-ssc 17269

This theorem is referenced by:  brssc  17273  ssc1  17280  ssc2  17281  ssctr  17284  issubc  17295