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LeanPool.SumsThreeSquares.MinkowskiConvex

Minkowski's theorem for the standard integer lattice in ℝⁿ #

This file specializes Minkowski's theorem on lattice points contained in convex symmetric bodies to the standard integer lattice ℤⁿ ⊆ EuclideanSpace ℝ (Fin n).

The main result, classical_exists_ne_zero_mem_lattice_of_measure_mul_two_pow_lt_measure, states that a symmetric convex set of volume greater than 2 ^ n contains a nonzero point all of whose coordinates are integers.

theorem LeanPool.SumsThreeSquares.classical_exists_ne_zero_mem_lattice_of_measure_mul_two_pow_lt_measure {n : ℕ} {s : Set (EuclideanSpace ℝ (Fin n))} (h_symm : ∀ x ∈ s, -x ∈ s) (h_conv : Convex ℝ s) (h : 2 ^ n < MeasureTheory.volume s) :
∃ (x : EuclideanSpace ℝ (Fin n)), x ≠ 0 ∧ x ∈ s ∧ ∀ (i : Fin n), ∃ (m : ℤ), ↑m = x.ofLp i