Some definitions of interest.
nat	Def  == {i:| 0i }
	Thm*   Type
	Thm*   S
nmod	Def nmod(m;n) == if n=0 then 0 else m rem n fi
	Thm* m,n:. nmod(m;n)
not	Def A == A  False
	Thm* A:Prop. (A)  Prop

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