Theorem iba 527

Description: Introduction of antecedent as conjunct. Theorem *4.73 of [WhiteheadRussell] p. 121. (Contributed by NM, 30-Mar-1994.)

Assertion

Ref	Expression
iba	⊢ (𝜑 → (𝜓 ↔ (𝜓 ∧ 𝜑)))

Proof of Theorem iba

Step	Hyp	Ref	Expression
1		pm3.21 471	. 2 ⊢ (𝜑 → (𝜓 → (𝜓 ∧ 𝜑)))
2		simpl 482	. 2 ⊢ ((𝜓 ∧ 𝜑) → 𝜓)
3	1, 2	impbid1 225	1 ⊢ (𝜑 → (𝜓 ↔ (𝜓 ∧ 𝜑)))

Syntax hints:   → wi 4   ↔ wb 206   ∧ wa 395

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 207  df-an 396

This theorem is referenced by:  ibar  528  biantru  529  biantrud  531  ancrb  547  pm5.54  1019  dedlem0a  1043  r19.29r  3096  unineq  4251  fvopab6  7002  fressnfv  7132  tpostpos  8225  odi  8543  nnmword  8597  ltmpi  10857  maducoeval2  22527  mdbr2  32225  mdsl2i  32251  poimirlem26  37640  poimirlem27  37641  itg2addnclem  37665  itg2addnclem3  37667  prjspeclsp  42600  rmydioph  43003  expdioph  43012  dmafv2rnb  47227