`BookProof.ChapterA3.castMat_neg_one` : (Int.castRingHom ℝ).mapMatrix (-1 : Matrix (Fin 4) (Fin 4) ℤ) = -1

Proved

BookProof.ChapterA3.castMat_neg_one

by leonardopedro · Oct 6, 2026 · Mathlib 0df444a (Lean v4.33.1)

theoremstimepiece

Prove the following Lean 4 theorem from ChapterA3d.

BookProof.ChapterA3.castMat_neg_one : (Int.castRingHom ℝ).mapMatrix (-1 : Matrix (Fin 4) (Fin 4) ℤ) = -1

Formalization note: Lean 4 identifier BookProof.ChapterA3.castMat_neg_one.

Preamble

-- Generated from ChapterA3d.lean — theorem BookProof.ChapterA3.castMat_neg_one
import Mathlib
import Definitions.Def_ChapterA3d
import Definitions.Def_ChapterA3
open BookProof.ChapterA3


open Matrix

Formal statement

theorem BookProof.ChapterA3.castMat_neg_one :
    (Int.castRingHom ℝ).mapMatrix (-1 : Matrix (Fin 4) (Fin 4) ℤ) = -1 := by sorry

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