Theorem cbvalv 1917

Description: Rule used to change bound variables, using implicit substitition. (Contributed by NM, 5-Aug-1993.)

Hypothesis

Ref	Expression
cbvalv.1	⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))

Assertion

Ref	Expression
cbvalv	⊢ (∀𝑥𝜑 ↔ ∀𝑦𝜓)

Distinct variable groups:   𝜑,𝑦   𝜓,𝑥

Allowed substitution hints:   𝜑(𝑥)   𝜓(𝑦)

Proof of Theorem cbvalv

Step	Hyp	Ref	Expression
1		ax-17 1526	. 2 ⊢ (𝜑 → ∀𝑦𝜑)
2		ax-17 1526	. 2 ⊢ (𝜓 → ∀𝑥𝜓)
3		cbvalv.1	. 2 ⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))
4	1, 2, 3	cbvalh 1753	1 ⊢ (∀𝑥𝜑 ↔ ∀𝑦𝜓)

Syntax hints:   → wi 4   ↔ wb 105  ∀wal 1351

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534

This theorem depends on definitions:  df-bi 117  df-nf 1461

This theorem is referenced by:  nfcjust  2307  cdeqal1  2953  dfss4st  3368  zfpow  4174  tfisi  4585  acexmid  5871  tfrlem3-2d  6310  tfrlemi1  6330  tfrexlem  6332  tfr1onlemaccex  6346  tfrcllemaccex  6359  findcard  6885  fisseneq  6928  genprndl  7517  genprndu  7518  zfz1iso  10814