d8f3bcec67
It is identical to default, but it is opaque. That is, when we use 'arbitrary A', we cannot rely on the particular value selected.
16 lines
320 B
Text
16 lines
320 B
Text
open nat
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definition f : nat → nat → nat,
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f _ 0 := 0,
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f 0 _ := 1,
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f _ _ := arbitrary nat
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theorem f_zero_right : ∀ a, f a 0 = 0,
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f_zero_right 0 := rfl,
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f_zero_right (succ _) := rfl
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theorem f_zero_succ (a : nat) : f 0 (a+1) = 1 :=
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rfl
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theorem f_succ_succ (a b : nat) : f (a+1) (b+1) = arbitrary nat :=
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rfl
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