is mentioned by

Def p q == case p: 3 q; 3 case q: 3 3; 3 3; 3 3;; 3 3;	[K_or]
Def p q == case p: 3 3; 3 case q: 3 3; 3 3; 3 3;; 3 q;	[K_and]
Def p == case p: 3 3; 3 3; 3 3;	[K_not]
Def p q == case p: 3 3; 3 case q: 3 3; 3 3; 3 3;; 3 q;	[K_imp]

In prior sections: Three

Try larger context: ClassicalProps(jlc)