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Tej Chajed
stdpp
Commits
2af4573e
Commit
2af4573e
authored
Jul 25, 2016
by
Robbert Krebbers
Browse files
More documentation of [coPset].
parent
ef823867
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theories/coPset.v
theories/coPset.v
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theories/coPset.v
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2af4573e
(* Copyright (c) 20122015, Robbert Krebbers. *)
(* This file is distributed under the terms of the BSD license. *)
(** This files implements an efficient implementation of finite/cofinite sets
of positive binary naturals [positive]. *)
(** This files implements the type [coPset] of efficient finite/cofinite sets
of positive binary naturals [positive]. These sets are:
 Closed under union, intersection and set complement.
 Closed under splitting of cofinite sets.
Also, they enjoy various nice properties, such as decidable equality and set
membership, as well as extensional equality (i.e. [X = Y ↔ ∀ x, x ∈ X ↔ x ∈ Y]).
Since [positive]s are bitstrings, we encode [coPset]s as trees that correspond
to the decision function that map bitstrings to bools. *)
From
stdpp
Require
Export
collections
.
From
stdpp
Require
Import
pmap
gmap
mapset
.
Local
Open
Scope
positive_scope
.
...
...
@@ 228,9 +237,9 @@ Proof.
refine
(
cast_if
(
decide
(
coPset_finite
(
`
X
))))
;
by
rewrite
coPset_finite_spec
.
Defined
.
(** * Pick element from infi
ti
nite sets *)
(*
just
depthfirst search
: using this to pick elements
results in very
unbalanced
trees. *)
(** * Pick element from infinite sets *)
(*
Implemented using
depthfirst search
, which
results in very
unbalanced
trees. *)
Fixpoint
coPpick_raw
(
t
:
coPset_raw
)
:
option
positive
:
=
match
t
with

coPLeaf
true

coPNode
true
_
_
=>
Some
1
...
...
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