26 lines
486 B
Text
26 lines
486 B
Text
constant g : nat → nat
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noncomputable definition f := g
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example : f = g := rfl
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attribute [irreducible] f
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example : f = g := rfl -- Error
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example (a : nat) (H : a = g a) : f a = a :=
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eq.subst H rfl -- Error
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attribute [semireducible] f
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example (a : nat) (H : a = g a) : f a = a :=
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eq.subst H rfl -- Error
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example : f = g := rfl
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attribute [reducible] f
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example : f = g := rfl
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example (a : nat) (H : a = g a) : f a = a :=
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@@eq.subst (λ x, f a = x) (eq.symm H) (eq.refl (f a))
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