Theorem 0heALT 39037

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

Assertion

Ref	Expression
0heALT	⊢ ∅ hereditary 𝐴

Proof of Theorem 0heALT

Step	Hyp	Ref	Expression
1		xphe 39035	. 2 ⊢ (∅ × 𝐴) hereditary 𝐴
2		0xp 5447	. . 3 ⊢ (∅ × 𝐴) = ∅
3		heeq1 39031	. . 3 ⊢ ((∅ × 𝐴) = ∅ → ((∅ × 𝐴) hereditary 𝐴 ↔ ∅ hereditary 𝐴))
4	2, 3	ax-mp 5	. 2 ⊢ ((∅ × 𝐴) hereditary 𝐴 ↔ ∅ hereditary 𝐴)
5	1, 4	mpbi 222	1 ⊢ ∅ hereditary 𝐴

Syntax hints:   ↔ wb 198   = wceq 1601  ∅c0 4141   × cxp 5353   hereditary whe 39026

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1839  ax-4 1853  ax-5 1953  ax-6 2021  ax-7 2055  ax-9 2116  ax-10 2135  ax-11 2150  ax-12 2163  ax-13 2334  ax-ext 2754  ax-sep 5017  ax-nul 5025  ax-pr 5138

This theorem depends on definitions:  df-bi 199  df-an 387  df-or 837  df-3an 1073  df-tru 1605  df-ex 1824  df-nf 1828  df-sb 2012  df-mo 2551  df-eu 2587  df-clab 2764  df-cleq 2770  df-clel 2774  df-nfc 2921  df-ne 2970  df-ral 3095  df-rex 3096  df-rab 3099  df-v 3400  df-dif 3795  df-un 3797  df-in 3799  df-ss 3806  df-nul 4142  df-if 4308  df-sn 4399  df-pr 4401  df-op 4405  df-br 4887  df-opab 4949  df-xp 5361  df-rel 5362  df-cnv 5363  df-dm 5365  df-rn 5366  df-res 5367  df-ima 5368  df-he 39027

This theorem is referenced by: (None)