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Try doing some basic maths questions in the Lean Theorem Prover. Functions, real numbers, equivalence relations and groups. Click on README.md and then on "Open in CoCalc with one click".

Project: Xena
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License: APACHE
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/-
Copyright (c) 2019 Scott Morrison. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Scott Morrison
-/
import data.set.intervals
import data.set.finite
import data.fintype
import tactic

/-!
# fintype instances for intervals

We provide `fintype` instances for `Ico l u`, for `l u : ℕ`, and for `l u : ℤ`.
-/

namespace set

instance Ico_ℕ_fintype (l u : ℕ) : fintype (Ico l u) :=
fintype.of_finset (finset.Ico l u) $
  (λ n, by { simp only [mem_Ico, finset.Ico.mem], })

instance Ico_ℤ_fintype (l u : ℤ) : fintype (Ico l u) :=
fintype.of_finset (finset.Ico_ℤ l u) $
  (λ n, by { simp only [mem_Ico, finset.Ico_ℤ.mem], })

-- TODO other useful instances: pnat, fin n, zmod?

end set