Syntax Definition wo 698

Description: Extend wff definition to include disjunction ('or').

Hypotheses

Ref	Expression
wph	wff 𝜑
wps	wff 𝜓

Assertion

Ref	Expression
wo	wff (𝜑 ∨ 𝜓)

This syntax is primitive. The first axiom using it is ax-io 699.