Theorem sb4av 2245

Description: Version of sb4a 2485 with a disjoint variable condition, which does not require ax-13 2377. The distinctor antecedent from sb4b 2480 is replaced by a disjoint variable condition in this theorem. (Contributed by NM, 2-Feb-2007.) (Revised by BJ, 15-Dec-2023.)

Assertion

Ref	Expression
sb4av	⊢ ([𝑡 / 𝑥]∀𝑡𝜑 → ∀𝑥(𝑥 = 𝑡 → 𝜑))

Distinct variable group:   𝑥,𝑡

Allowed substitution hints:   𝜑(𝑥,𝑡)

Proof of Theorem sb4av

Step	Hyp	Ref	Expression
1		sp 2184	. . 3 ⊢ (∀𝑡𝜑 → 𝜑)
2	1	sbimi 2075	. 2 ⊢ ([𝑡 / 𝑥]∀𝑡𝜑 → [𝑡 / 𝑥]𝜑)
3		sb6 2086	. 2 ⊢ ([𝑡 / 𝑥]𝜑 ↔ ∀𝑥(𝑥 = 𝑡 → 𝜑))
4	2, 3	sylib 218	1 ⊢ ([𝑡 / 𝑥]∀𝑡𝜑 → ∀𝑥(𝑥 = 𝑡 → 𝜑))

Syntax hints:   → wi 4  ∀wal 1538  [wsb 2065

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2008  ax-12 2178

This theorem depends on definitions:  df-bi 207  df-an 396  df-ex 1780  df-sb 2066

This theorem is referenced by:  bj-hbsb2av  36837