Theorem sscrel 17860

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 17857	. 2 ⊢ ⊆cat = {⟨ℎ, 𝑗⟩ ∣ ∃𝑡(𝑗 Fn (𝑡 × 𝑡) ∧ ∃𝑠 ∈ 𝒫 𝑡ℎ ∈ X𝑥 ∈ (𝑠 × 𝑠)𝒫 (𝑗‘𝑥))}
2	1	relopabiv 5798	1 ⊢ Rel ⊆cat

Syntax hints:   ∧ wa 400  ∃wex 1802   ∈ wcel 2145  ∃wrex 3089  𝒫 cpw 4558   × cxp 5650  Rel wrel 5657   Fn wfn 6520  ‘cfv 6525  Xcixp 8883   ⊆_cat cssc 17854

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1818  ax-4 1832  ax-5 1933  ax-6 1990  ax-7 2031  ax-8 2147  ax-9 2155  ax-ext 2737

This theorem depends on definitions:  df-bi 210  df-an 401  df-tru 1566  df-ex 1803  df-sb 2094  df-clab 2744  df-cleq 2757  df-clel 2840  df-v 3459  df-ss 3924  df-opab 5168  df-xp 5658  df-rel 5659  df-ssc 17857

This theorem is referenced by:  brssc  17861  ssc1  17868  ssc2  17869  ssctr  17872  issubc  17882  iinfssc  49686