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@mukeshtiwari
Created August 18, 2016 07:03
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Finite type no duplicate element
Theorem noduplicate : forall (l1 l2 : list bool), NoDup l1 -> NoDup l2 ->
(forall a : bool, In a l1) -> length l2 <= length l1.
@mukeshtiwari
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Proof.
intros l1 l2 H1 H2 H3.
apply NoDup_incl_length. assumption.

l1, l2 : list bool

H1 : NoDup l1
H2 : NoDup l2
H3 : forall a : bool, In a l1

incl l2 l1

@mukeshtiwari
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Finally proved :)

                                       (forall a : bool, In a l1) -> length l2 <= length l1.

Proof.
intros l1 l2 H1 H2 H3.
apply NoDup_incl_length. assumption.
unfold incl. intros. specialize (H3 a).
assumption.
Qed.

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