Definition df-or-D2.3 145

Description: Definition of Disjunction, '∨'. Read as "or".

Assertion

Ref	Expression
df-or-D2.3	⊢ ((𝜑 ∨ 𝜓) ↔ (¬ 𝜑 → 𝜓))

Detailed syntax breakdown of Definition df-or-D2.3

Step	Hyp	Ref	Expression
1		wff-ph	. . 3 wff 𝜑
2		wff-ps	. . 3 wff 𝜓
3	1, 2	wff-or 144	. 2 wff (𝜑 ∨ 𝜓)
4	1	wff-neg 9	. . 3 wff ¬ 𝜑
5	4, 2	wff-imp 10	. 2 wff (¬ 𝜑 → 𝜓)
6	3, 5	wff-bi 104	1 wff ((𝜑 ∨ 𝜓) ↔ (¬ 𝜑 → 𝜓))

This definition is referenced by:  orintl-P2.11a  146  orintr-P2.11b  148  orelim-P2.11c  150