Theorem nfdisj1 5009

Description: Bound-variable hypothesis builder for disjoint collection. (Contributed by Mario Carneiro, 14-Nov-2016.)

Assertion

Ref	Expression
nfdisj1	⊢ Ⅎ𝑥Disj 𝑥 ∈ 𝐴 𝐵

Proof of Theorem nfdisj1

Dummy variable 𝑦 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		df-disj 4996	. 2 ⊢ (Disj 𝑥 ∈ 𝐴 𝐵 ↔ ∀𝑦∃*𝑥 ∈ 𝐴 𝑦 ∈ 𝐵)
2		nfrmo1 3274	. . 3 ⊢ Ⅎ𝑥∃*𝑥 ∈ 𝐴 𝑦 ∈ 𝐵
3	2	nfal 2325	. 2 ⊢ Ⅎ𝑥∀𝑦∃*𝑥 ∈ 𝐴 𝑦 ∈ 𝐵
4	1, 3	nfxfr 1859	1 ⊢ Ⅎ𝑥Disj 𝑥 ∈ 𝐴 𝐵

Syntax hints:  ∀wal 1540  Ⅎwnf 1790   ∈ wcel 2114  ∃*wrmo 3056  Disj wdisj 4995

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1802  ax-4 1816  ax-5 1917  ax-6 1975  ax-7 2020  ax-10 2145  ax-11 2162  ax-12 2179

This theorem depends on definitions:  df-bi 210  df-or 847  df-ex 1787  df-nf 1791  df-mo 2540  df-rmo 3061  df-disj 4996

This theorem is referenced by:  disjabrex  30495  disjabrexf  30496  hasheuni  31623  ldgenpisyslem1  31701  measvunilem  31750  measvunilem0  31751  measvuni  31752  measinblem  31758  voliune  31767  volfiniune  31768  volmeas  31769  dstrvprob  32008  ismeannd  43547