Q == (P 
Q) & (P Q)
A,B:Prop. (A B) 
Prop
A == A FalseA:Prop. (A) Prop
= y == x = yt,x:Term. (t = x) Prop
f(t))t:Term. s(t) Termt,r:Term. SUBX(t; r) Term| Some definitions of interest. | |
| iff | Def P Q == (P Q) & (P Q) |
| Thm* A,B:Prop. (A B) Prop | |
| not | Def A == A False |
| Thm* A:Prop. (A) Prop | |
| repst | Def x = y == x = y |
| Thm* t,x:Term. (t = x) Prop | |
| s | Def s(t) == SUBX(f(t); f(t)) |
| Thm* t:Term. s(t) Term | |
| subx | Def SUBX(t; e) == t[e/X] |
| Thm* t,r:Term. SUBX(t; r) Term |
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