diff options
Diffstat (limited to 'doc/faq/interval_discr.v')
-rw-r--r-- | doc/faq/interval_discr.v | 24 |
1 files changed, 12 insertions, 12 deletions
diff --git a/doc/faq/interval_discr.v b/doc/faq/interval_discr.v index 972300dac..ed2c0e37e 100644 --- a/doc/faq/interval_discr.v +++ b/doc/faq/interval_discr.v @@ -69,7 +69,7 @@ Qed. (** Definition of having finite cardinality [n+1] for a set [A] *) Definition card (A:Set) n := - exists f, + exists f, (forall x:A, f x <= n) /\ (forall x y:A, f x = f y -> x = y) /\ (forall m, m <= n -> exists x:A, f x = m). @@ -86,7 +86,7 @@ split. (* bounded *) intro x; apply (proj2_sig x). split. -(* injectivity *) +(* injectivity *) intros (p,Hp) (q,Hq). simpl. intro Hpq. @@ -123,7 +123,7 @@ left. apply eq_S. assumption. right. - intro HeqS. + intro HeqS. injection HeqS; intro Heq. apply Hneq. apply dep_pair_intro. @@ -133,7 +133,7 @@ Qed. (** Showing that the cardinality relation is functional on decidable sets *) Lemma card_inj_aux : - forall (A:Type) f g n, + forall (A:Type) f g n, (forall x:A, f x <= 0) -> (forall x y:A, f x = f y -> x = y) -> (forall m, m <= S n -> exists x:A, g x = m) @@ -175,7 +175,7 @@ lemma by generalizing over a first-order definition of [x<>y], say Qed. Lemma dec_restrict : - forall (A:Set), + forall (A:Set), (forall x y :A, {x=y}+{x<>y}) -> forall z (x y :{a:A|a<>z}), {x=y}+{x<>y}. Proof. @@ -185,7 +185,7 @@ left; apply neq_dep_intro; assumption. right; intro Heq; injection Heq; exact Hneq. Qed. -Lemma pred_inj : forall n m, +Lemma pred_inj : forall n m, 0 <> n -> 0 <> m -> pred m = pred n -> m = n. Proof. destruct n. @@ -242,13 +242,13 @@ destruct (le_lt_or_eq _ _ Hfx). contradiction (lt_not_le (f y) (f z)). Qed. -Theorem card_inj : forall m n (A:Set), +Theorem card_inj : forall m n (A:Set), (forall x y :A, {x=y}+{x<>y}) -> - card A m -> card A n -> m = n. + card A m -> card A n -> m = n. Proof. -induction m; destruct n; +induction m; destruct n; intros A Hdec - (f,(Hfbound,(Hfinj,Hfsurj))) + (f,(Hfbound,(Hfinj,Hfsurj))) (g,(Hgbound,(Hginj,Hgsurj))). (* 0/0 *) reflexivity. @@ -265,7 +265,7 @@ apply dec_restrict. assumption. (* cardinality of {x:A|x<>xSn} is m *) pose (f' := fun x' : {x:A|x<>xSn} => - let (x,Hneq) := x' in + let (x,Hneq) := x' in if le_lt_dec (f xSn) (f x) then pred (f x) else f x). @@ -361,7 +361,7 @@ destruct (le_lt_dec (f xSn) (f x)) as [Hle'|Hlt']. assumption. (* cardinality of {x:A|x<>xSn} is n *) pose (g' := fun x' : {x:A|x<>xSn} => - let (x,Hneq) := x' in + let (x,Hneq) := x' in if Hdec x xSn then 0 else g x). exists g'. split. |