10 lines
284 B
Text
10 lines
284 B
Text
variable {α : Type _} [Mul α] [Inhabited α]
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abbrev Left (a : α) : α := a * default
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abbrev Right (a : α): α := default * a
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theorem mul_comm (a b : α) : a * b = b * a := sorry
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set_option trace.Meta.Tactic.simp true
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example (a : α) : Left a = Right a := by
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simp [mul_comm]
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