Theorem sscrel 17720

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 17717	. 2 ⊢ ⊆cat = {⟨ℎ, 𝑗⟩ ∣ ∃𝑡(𝑗 Fn (𝑡 × 𝑡) ∧ ∃𝑠 ∈ 𝒫 𝑡ℎ ∈ X𝑥 ∈ (𝑠 × 𝑠)𝒫 (𝑗‘𝑥))}
2	1	relopabiv 5759	1 ⊢ Rel ⊆cat

Syntax hints:   ∧ wa 395  ∃wex 1780   ∈ wcel 2111  ∃wrex 3056  𝒫 cpw 4547   × cxp 5612  Rel wrel 5619   Fn wfn 6476  ‘cfv 6481  Xcixp 8821   ⊆_cat cssc 17714

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1796  ax-4 1810  ax-5 1911  ax-6 1968  ax-7 2009  ax-8 2113  ax-9 2121  ax-ext 2703

This theorem depends on definitions:  df-bi 207  df-an 396  df-tru 1544  df-ex 1781  df-sb 2068  df-clab 2710  df-cleq 2723  df-clel 2806  df-v 3438  df-ss 3914  df-opab 5152  df-xp 5620  df-rel 5621  df-ssc 17717

This theorem is referenced by:  brssc  17721  ssc1  17728  ssc2  17729  ssctr  17732  issubc  17742  iinfssc  49168