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.
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.
Finite
.
Sigma
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Imports
Init
Mathlib.Data.Fintype.EquivFin
Mathlib.Data.Fintype.Sigma
Mathlib.Logic.Equiv.Sigma
Imported by
Finite
.
instSigma
Finite
.
instPSigma
Finite
.
Set
.
finite_sigma
Set
.
Finite
.
sigma
Finiteness of sigma types
#
source
instance
Finite
.
instSigma
{
α
:
Type
u_1}
{
β
:
α
→
Type
u_2
}
[
Finite
α
]
[
∀ (
a
:
α
),
Finite
(
β
a
)
]
:
Finite
((
a
:
α
) ×
β
a
)
source
instance
Finite
.
instPSigma
{
ι
:
Sort
u_3}
{
π
:
ι
→
Sort
u_4
}
[
Finite
ι
]
[
∀ (
i
:
ι
),
Finite
(
π
i
)
]
:
Finite
((
i
:
ι
) ×'
π
i
)
source
instance
Finite
.
Set
.
finite_sigma
{
α
:
Type
u_1}
{
β
:
α
→
Type
u_2
}
(
s
:
Set
α
)
(
t
:
(
i
:
α
) →
Set
(
β
i
)
)
[
Finite
↑
s
]
[
∀ (
i
:
α
),
Finite
↑
(
t
i
)
]
:
Finite
↑
(
s
.
sigma
t
)
source
theorem
Set
.
Finite
.
sigma
{
α
:
Type
u_1}
{
β
:
α
→
Type
u_2
}
{
s
:
Set
α
}
{
t
:
(
i
:
α
) →
Set
(
β
i
)
}
(
hs
:
s
.
Finite
)
(
ht
:
∀
i
∈
s
,
(
t
i
)
.
Finite
)
:
(
s
.
sigma
t
)
.
Finite
A finite sum of finite sets is finite