leanprover-community / leanprover-community/mathlib4
linarith? fails while linarith finds the proofs
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Since Aug 23, 2026.
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Description
Minimal reproducers
Plain linarith proves both of these; linarith? fails with
linarith failed to find a contradiction:
import Mathlib.Tactic.Linarith
example (x y u v : ℚ) (hu : u < v) (hv : v < u) : x < y := by linarith? -- fails
example (a u v : ℚ) (gu : u < v) (h : a < 0) : a ≤ 0 := by linarith? -- fails
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