19 lines
385 B
Coq
19 lines
385 B
Coq
Inductive point : Set :=
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| Point : nat -> nat -> point.
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Inductive line : Set :=
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| Line : point -> point -> line.
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Inductive plane : Set :=
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(* Plane through 3 non-collinear points *)
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| Plane3Pt : point -> point -> point -> plane.
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Definition projX (a:point) : nat :=
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match a with
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| Point x _ => x
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end.
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Definition projY (a:point) : nat :=
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match a with
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| Point _ y => y
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end.
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