10 lines
297 B
Text
10 lines
297 B
Text
theorem Fin.ext_iff : (Fin.mk m h₁ : Fin k) = Fin.mk n h₂ ↔ m = n :=
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Fin.mk.injEq _ _ _ _ ▸ Iff.rfl
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example (h : m = n) : (Fin.mk m h₁ : Fin k) = Fin.mk n h₂ := by
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apply Fin.ext_iff.2
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exact h
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example (h : m = n) : (Fin.mk m h₁ : Fin k) = Fin.mk n h₂ := by
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simp
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exact h
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