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TauCeti.Data.Nat.Cast.Order.Field

A lower bound from a natural reciprocal below one #

A nonzero natural number whose reciprocal, cast into a preordered division semiring, is less than one is at least two. This converts the reciprocal-sum hypothesis for a hyperbolic triangle group into the parameter bounds needed for its trigonometric matrix representation.

theorem TauCeti.two_le_of_cast_inv_lt_one {α : Type u_1} [DivisionSemiring α] [Preorder α] {p : ℕ} (hp : p ≠ 0) (h : (↑p)⁻¹ < 1) :
2 ≤ p

A nonzero natural number whose reciprocal is less than one is at least two.