Theorem sscrel 17865

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 17862	. 2 ⊢ ⊆cat = {⟨ℎ, 𝑗⟩ ∣ ∃𝑡(𝑗 Fn (𝑡 × 𝑡) ∧ ∃𝑠 ∈ 𝒫 𝑡ℎ ∈ X𝑥 ∈ (𝑠 × 𝑠)𝒫 (𝑗‘𝑥))}
2	1	relopabiv 5807	1 ⊢ Rel ⊆cat

Syntax hints:   ∧ wa 400  ∃wex 1809   ∈ wcel 2143  ∃wrex 3089  𝒫 cpw 4562   × cxp 5659  Rel wrel 5666   Fn wfn 6531  ‘cfv 6536  Xcixp 8891   ⊆_cat cssc 17859

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1825  ax-4 1839  ax-5 1940  ax-6 1997  ax-7 2038  ax-8 2145  ax-9 2153  ax-ext 2735

This theorem depends on definitions:  df-bi 210  df-an 401  df-tru 1573  df-ex 1810  df-sb 2097  df-clab 2742  df-cleq 2755  df-clel 2838  df-v 3457  df-ss 3922  df-opab 5174  df-xp 5667  df-rel 5668  df-ssc 17862

This theorem is referenced by:  brssc  17866  ssc1  17873  ssc2  17874  ssctr  17877  issubc  17887  iinfssc  49855