Theorem sscrel 17870

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 17867	. 2 ⊢ ⊆cat = {⟨ℎ, 𝑗⟩ ∣ ∃𝑡(𝑗 Fn (𝑡 × 𝑡) ∧ ∃𝑠 ∈ 𝒫 𝑡ℎ ∈ X𝑥 ∈ (𝑠 × 𝑠)𝒫 (𝑗‘𝑥))}
2	1	relopabiv 5808	1 ⊢ Rel ⊆cat

Syntax hints:   ∧ wa 400  ∃wex 1806   ∈ wcel 2149  ∃wrex 3095  𝒫 cpw 4567   × cxp 5660  Rel wrel 5667   Fn wfn 6532  ‘cfv 6537  Xcixp 8895   ⊆_cat cssc 17864

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1822  ax-4 1836  ax-5 1937  ax-6 1994  ax-7 2035  ax-8 2151  ax-9 2159  ax-ext 2741

This theorem depends on definitions:  df-bi 210  df-an 401  df-tru 1570  df-ex 1807  df-sb 2098  df-clab 2748  df-cleq 2761  df-clel 2844  df-v 3465  df-ss 3930  df-opab 5178  df-xp 5668  df-rel 5669  df-ssc 17867

This theorem is referenced by:  brssc  17871  ssc1  17878  ssc2  17879  ssctr  17882  issubc  17892  iinfssc  49754