t:Term. f(t) 
Term Termt,x:Term. (t reps x) Propt,r:Term. t/r Term| Some definitions of interest. | |
| f | Def f(t) == SUBX(q(t); SUBX(X; Q(X))) |
| Thm* t:Term. f(t) Term | |
| repst | Def x reps y == x reps y Term |
| Thm* t,x:Term. (t reps x) Prop | |
| subx | Def t/e == t[e/X] |
| Thm* t,r:Term. t/r Term |
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