Theorem biorfi 944

Description: The dual of biorf 942 is not biantr 811 but iba 532 (and ibar 533). So there should also be a "biorfr". (Note that these four statements can actually be strengthened to biconditionals.) (Contributed by BJ, 26-Oct-2019.)

Hypothesis

Ref	Expression
biorfi.1	⊢ ¬ 𝜑

Assertion

Ref	Expression
biorfi	⊢ (𝜓 ↔ (𝜑 ∨ 𝜓))

Proof of Theorem biorfi

Step	Hyp	Ref	Expression
1		biorfi.1	. 2 ⊢ ¬ 𝜑
2		biorf 942	. 2 ⊢ (¬ 𝜑 → (𝜓 ↔ (𝜑 ∨ 𝜓)))
3	1, 2	ax-mp 5	1 ⊢ (𝜓 ↔ (𝜑 ∨ 𝜓))

Syntax hints:  ¬ wn 3   ↔ wb 207   ∨ wo 853

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 208  df-or 854

This theorem is referenced by:  biorfri  945  opthprc  5682  frxp2  8084  bj-falor  36895  usgrexmpl2nb1  48523  usgrexmpl2nb2  48524  usgrexmpl2nb4  48526  usgrexmpl2nb5  48527  gpg5nbgrvtx03starlem1  48559  gpg5nbgrvtx03starlem2  48560  gpg5nbgrvtx03starlem3  48561  gpg5nbgrvtx13starlem1  48562  gpg5nbgrvtx13starlem2  48563  gpg5nbgrvtx13starlem3  48564  gpg5edgnedg  48621