## Compfiles: Catalog Of Math Problems Formalized In Lean

## Imo1979P1

```
import Mathlib.Tactic
/-!
# International Mathematical Olympiad 1979, Problem 1
Suppose that p and q are positive integers such that
p / q = 1 - 1/2 + 1/3 - 1/4 + ... - 1/1318 + 1/1319.
Prove that p is divisible by 1979.
-/
namespace Imo1979P1
theorem imo1979_p1 (p q : ℤ) (hp : 0 < p) (hq : 0 < q)
(h : (p : ℚ) / q = ∑ i ∈ Finset.range 1319, (-1 : ℚ)^i / (i + 1)) :
1979 ∣ p := sorry
end Imo1979P1
```

File author(s): David Renshaw

This problem has a complete formalized solution.

Open with the in-brower editor at live.lean-lang.org: