mirror of https://github.com/nmvdw/HITs-Examples
60 lines
1.3 KiB
Coq
60 lines
1.3 KiB
Coq
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Require Import FSets list_representation.
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Require Import kuratowski.length misc.dec_kuratowski.
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From interfaces Require Import lattice_interface.
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From subobjects Require Import sub b_finite enumerated k_finite.
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Require Import HoTT.Spaces.Card.
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Section contents.
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Context `{Univalence}.
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Definition isKf_card (X : Card) : hProp.
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Proof.
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strip_truncations.
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refine (Kf X).
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Defined.
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Definition Kf_card := BuildhSet (@sig Card isKf_card).
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Definition Kf_card' := BuildhSet (Trunc 0 (@sig hSet (fun X => Kf X))).
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Definition f : Kf_card -> Kf_card'.
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Proof.
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intros [X HX].
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unfold Kf_card'.
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revert HX. strip_truncations.
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intros HX.
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apply tr.
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exists X.
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apply HX.
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Defined.
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Definition g : Kf_card' -> Kf_card.
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Proof.
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unfold Kf_card, Kf_card'.
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intros X. strip_truncations.
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destruct X as [X HX].
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exists (tr X). apply HX.
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Defined.
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Instance f_equiv : IsEquiv f.
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Proof.
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apply isequiv_biinv.
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split; exists g.
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- unfold Sect. unfold Kf_card. simpl.
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intros [X HX].
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revert HX. strip_truncations. intros HX.
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simpl. reflexivity.
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- intros X. strip_truncations. simpl.
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reflexivity.
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Defined.
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Lemma kf_card_equiv :
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Kf_card = Kf_card'.
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Proof.
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apply path_hset.
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simple refine (BuildEquiv Kf_card Kf_card' f _).
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Defined.
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End contents.
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