is mentioned by

Thm* (P P) False	[prop_iff_contra]
Thm* (A B) (B C) (A C)	[prop_iff_trans]
Thm* B (A B & C) (A C)	[prop_and_iff]
Thm* t,r,t',r':Term. t = t' & r = r' SUBX(t; r) = SUBX(t'; r')	[qsubx_repst]
Def RepsTruth(L; Tr; tr) == (S:Term. (t:Term. S = t) L(SUBX(tr; S))) & RespectsNot(Tr; L) & ReflectsProp(Tr; tr; Tr)	[RepsTruth]
Def ReflectsProp(P; qP; Tr) == t,qt:Term. qt = t {Tr(SUBX(qP; qt)) Tr(t)}	[ReflectsProp]

In prior sections: core