Theorem sbiev 2320

Description: Conversion of implicit substitution to explicit substitution. Version of sbie 2507 with a disjoint variable condition, not requiring ax-13 2377. See sbievw 2099 for a version with a disjoint variable condition requiring fewer axioms. (Contributed by NM, 30-Jun-1994.) (Revised by Wolf Lammen, 18-Jan-2023.) Remove dependence on ax-10 2147 and shorten proof. (Revised by BJ, 18-Jul-2023.) (Proof shortened by SN, 24-Jul-2025.)

Hypotheses

Ref	Expression
sbiev.1	⊢ Ⅎ𝑥𝜓
sbiev.2	⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))

Assertion

Ref	Expression
sbiev	⊢ ([𝑦 / 𝑥]𝜑 ↔ 𝜓)

Distinct variable group:   𝑥,𝑦

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

Proof of Theorem sbiev

Step	Hyp	Ref	Expression
1		sbiev.2	. . 3 ⊢ (𝑥 = 𝑦 → (𝜑 ↔ 𝜓))
2	1	sbbiiev 2098	. 2 ⊢ ([𝑦 / 𝑥]𝜑 ↔ [𝑦 / 𝑥]𝜓)
3		sbiev.1	. . 3 ⊢ Ⅎ𝑥𝜓
4	3	sbf 2278	. 2 ⊢ ([𝑦 / 𝑥]𝜓 ↔ 𝜓)
5	2, 4	bitri 275	1 ⊢ ([𝑦 / 𝑥]𝜑 ↔ 𝜓)

Syntax hints:   → wi 4   ↔ wb 206  Ⅎwnf 1785  [wsb 2068

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1912  ax-6 1969  ax-7 2010  ax-12 2185

This theorem depends on definitions:  df-bi 207  df-an 396  df-ex 1782  df-nf 1786  df-sb 2069

This theorem is referenced by:  sbiedw  2322  sbco2v  2337  mo4f  2568  cbvrabwOLD  3426  reu2  3672  rmo4f  3682  sbcralt  3811  sbcreu  3815  sbcel12  4352  sbceqg  4353  sbcbr123  5140  frpoins2fg  6302  tfis2f  7800  tfinds  7804  setinds2f  9662  frins2f  9668  clwwlknonclwlknonf1o  30447  dlwwlknondlwlknonf1o  30450  funcnv4mpt  32756  nn0min  32909  ballotlemodife  34658  bnj1321  35185  bj-sbeqALT  37223  scottabf  44685