is mentioned by

Thm* i,j:, F:({i..j}Prop). (k:{i..j}. Dec(F(k))) Dec(k:{i..j}. F(k))	[decidable__all_int_seg]
Thm* i,j:, F:({i..j}Prop). (k:{i..j}. Dec(F(k))) Dec(k:{i..j}. F(k))	[decidable__ex_int_seg]

In prior sections: core int 1 bool 1

Try larger context: StandardLIB