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theorem proved term proof

neg_contains_neg

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formal statement (Lean)

  77theorem neg_contains_neg {x : ℝ} {I : Interval} (hx : I.contains x) : (-I).contains (-x) := by

proof body

Term-mode proof.

  78  constructor
  79  · simp only [neg_lo, Rat.cast_neg]
  80    exact neg_le_neg hx.2
  81  · simp only [neg_hi, Rat.cast_neg]
  82    exact neg_le_neg hx.1
  83
  84/-- Subtraction of intervals: [a,b] - [c,d] = [a-d, b-c] -/

depends on (11)

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