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Rice Wine
Iris
Commits
f31e57b6
Commit
f31e57b6
authored
Nov 22, 2016
by
Robbert Krebbers
Browse files
More set_Forall and set_Exists stuff for finite sets.
parent
f072ab70
Changes
1
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prelude/fin_collections.v
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f31e57b6
...
...
@@ 249,18 +249,38 @@ Section filter.
End
filter
.
(** * Decision procedures *)
Global
Instance
set_Forall_dec
`
(
P
:
A
→
Prop
)
`
{
∀
x
,
Decision
(
P
x
)}
X
:
Decision
(
set_Forall
P
X
)

100
.
Lemma
set_Forall_elements
P
X
:
set_Forall
P
X
↔
Forall
P
(
elements
X
).
Proof
.
rewrite
Forall_forall
.
by
setoid_rewrite
elem_of_elements
.
Qed
.
Lemma
set_Exists_elements
P
X
:
set_Exists
P
X
↔
Exists
P
(
elements
X
).
Proof
.
rewrite
Exists_exists
.
by
setoid_rewrite
elem_of_elements
.
Qed
.
Lemma
set_Forall_Exists_dec
{
P
Q
:
A
→
Prop
}
(
dec
:
∀
x
,
{
P
x
}
+
{
Q
x
})
X
:
{
set_Forall
P
X
}
+
{
set_Exists
Q
X
}.
Proof
.
refine
(
cast_if
(
Forall_Exists_dec
dec
(
elements
X
)))
;
[
by
apply
set_Forall_elements

by
apply
set_Exists_elements
].
Defined
.
Lemma
not_set_Forall_Exists
P
`
{
dec
:
∀
x
,
Decision
(
P
x
)}
X
:
¬
set_Forall
P
X
→
set_Exists
(
not
∘
P
)
X
.
Proof
.
intro
.
by
destruct
(
set_Forall_Exists_dec
dec
X
).
Qed
.
Lemma
not_set_Exists_Forall
P
`
{
dec
:
∀
x
,
Decision
(
P
x
)}
X
:
¬
set_Exists
P
X
→
set_Forall
(
not
∘
P
)
X
.
Proof
.
by
destruct
(@
set_Forall_Exists_dec
(
not
∘
P
)
_
(
λ
x
,
swap_if
(
decide
(
P
x
)))
X
).
Qed
.
Global
Instance
set_Forall_dec
(
P
:
A
→
Prop
)
`
{
∀
x
,
Decision
(
P
x
)}
X
:
Decision
(
set_Forall
P
X
)

100
.
Proof
.
refine
(
cast_if
(
decide
(
Forall
P
(
elements
X
))))
;
abstract
(
unfold
set_Forall
;
setoid_rewrite
<
elem_of_elements
;
by
rewrite
<
Forall_forall
).
by
rewrite
set_Forall_elements
.
Defined
.
Global
Instance
set_Exists_dec
`
(
P
:
A
→
Prop
)
`
{
∀
x
,
Decision
(
P
x
)}
X
:
Decision
(
set_Exists
P
X
)

100
.
Proof
.
refine
(
cast_if
(
decide
(
Exists
P
(
elements
X
))))
;
abstract
(
unfold
set_Exists
;
setoid_rewrite
<
elem_of_elements
;
by
rewrite
<
Exists_exists
).
by
rewrite
set_Exists_elements
.
Defined
.
End
fin_collection
.
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