is mentioned by

Thm* x,y:. x y = 3 x = 3 y = 3	[K_or_equal_Three_2]
Thm* x,y:. x y = 3 x = 3 & y = 3	[K_and_equal_Three_2]
Thm* p,q:. p q	[K_or_wf]
Thm* p,q:. p q	[K_and_wf]
Thm* p:. p	[K_not_wf]
Thm* p,q:. p q	[K_imp_wf]

In prior sections: Three

Try larger context: ClassicalProps(jlc)