Theorem 0he 44536

Description: The empty relation is hereditary in any class. (Contributed by RP, 27-Mar-2020.)

Assertion

Ref	Expression
0he	⊢ ∅ hereditary 𝐴

Proof of Theorem 0he

Step	Hyp	Ref	Expression
1		0ima 6079	. . 3 ⊢ (∅ “ 𝐴) = ∅
2		0ss 4356	. . 3 ⊢ ∅ ⊆ 𝐴
3	1, 2	eqsstri 3982	. 2 ⊢ (∅ “ 𝐴) ⊆ 𝐴
4		df-he 44527	. 2 ⊢ (∅ hereditary 𝐴 ↔ (∅ “ 𝐴) ⊆ 𝐴)
5	3, 4	mpbir 234	1 ⊢ ∅ hereditary 𝐴

This proof depends on syntax axioms:   ⊆ wss 3904  ∅c0 4285   “ cima 5663   hereditary whe 44526

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1824  ax-4 1838  ax-5 1939  ax-6 1996  ax-7 2037  ax-8 2144  ax-9 2152  ax-ext 2734  ax-sep 5256  ax-pr 5403

This proof depends on definitions:  df-bi 210  df-an 401  df-or 861  df-3an 1104  df-tru 1572  df-fal 1582  df-ex 1809  df-sb 2096  df-clab 2741  df-cleq 2754  df-clel 2837  df-ral 3079  df-rex 3089  df-rab 3416  df-v 3456  df-dif 3907  df-un 3909  df-in 3911  df-ss 3921  df-nul 4286  df-if 4487  df-sn 4589  df-pr 4591  df-op 4595  df-br 5109  df-opab 5173  df-xp 5666  df-cnv 5668  df-dm 5670  df-rn 5671  df-res 5672  df-ima 5673  df-he 44527

This theorem is used by: (None)