Theorem bdeq0 10658

Description: Boundedness of the formula expressing that a setvar is equal to the empty class. (Contributed by BJ, 21-Nov-2019.)

Assertion

Ref	Expression
bdeq0	⊢ BOUNDED 𝑥 = ∅

Proof of Theorem bdeq0

Step	Hyp	Ref	Expression
1		bdcnul 10656	. . 3 ⊢ BOUNDED ∅
2	1	bdss 10655	. 2 ⊢ BOUNDED 𝑥 ⊆ ∅
3		0ss 3282	. . 3 ⊢ ∅ ⊆ 𝑥
4		eqss 3014	. . 3 ⊢ (𝑥 = ∅ ↔ (𝑥 ⊆ ∅ ∧ ∅ ⊆ 𝑥))
5	3, 4	mpbiran2 882	. 2 ⊢ (𝑥 = ∅ ↔ 𝑥 ⊆ ∅)
6	2, 5	bd0r 10616	1 ⊢ BOUNDED 𝑥 = ∅

Syntax hints:   = wceq 1284   ⊆ wss 2973  ∅c0 3251  BOUNDED wbd 10603

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in1 576  ax-in2 577  ax-io 662  ax-5 1376  ax-7 1377  ax-gen 1378  ax-ie1 1422  ax-ie2 1423  ax-8 1435  ax-10 1436  ax-11 1437  ax-i12 1438  ax-bndl 1439  ax-4 1440  ax-17 1459  ax-i9 1463  ax-ial 1467  ax-i5r 1468  ax-ext 2063  ax-bd0 10604  ax-bdim 10605  ax-bdn 10608  ax-bdal 10609  ax-bdeq 10611

This theorem depends on definitions:  df-bi 115  df-tru 1287  df-fal 1290  df-nf 1390  df-sb 1686  df-clab 2068  df-cleq 2074  df-clel 2077  df-nfc 2208  df-ral 2353  df-v 2603  df-dif 2975  df-in 2979  df-ss 2986  df-nul 3252  df-bdc 10632

This theorem is referenced by:  bj-bd0el  10659  bj-nn0suc0  10745