28 lines
658 B
Text
28 lines
658 B
Text
open sigma
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constant hom.{l₁ l₂} {A : Type.{l₁}} {B : Type.{l₂}} (a : A) (b : B) : Type.{max l₁ l₂}
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definition arrow_ob [reducible] (A B : Type) : Type :=
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Σ (a : A) (b : B), hom a b
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definition src1 {A B : Type} (x : arrow_ob A B) : A :=
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match x with
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⟨a, b, h⟩ := a
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end
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definition src2 {A B : Type} : arrow_ob A B → A,
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src2 ⟨a, _, _⟩ := a
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definition src3 {A B : Type} (x : arrow_ob A B) : A :=
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match x with
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⟨a, _, _⟩ := a
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end
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example (A B : Type) (x : arrow_ob A B) : src1 x = src2 x :=
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rfl
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example (A B : Type) (x : arrow_ob A B) : src1 x = src3 x :=
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rfl
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example (A B : Type) (x : arrow_ob A B) : src2 x = src3 x :=
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rfl
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