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.
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.
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Imports
Init
Mathlib.Data.Rat.Cast.CharZero
Mathlib.Algebra.BigOperators.Group.Finset.Defs
Imported by
Rat
.
cast_list_sum
Rat
.
cast_multiset_sum
Rat
.
cast_sum
Rat
.
cast_list_prod
Rat
.
cast_multiset_prod
Rat
.
cast_prod
Casting lemmas for rational numbers involving sums and products
#
source
@[simp]
theorem
Rat
.
cast_list_sum
{α :
Type
u_2}
[
DivisionRing
α
]
[
CharZero
α
]
(s :
List
ℚ
)
:
↑
s
.
sum
=
(
List.map
Rat.cast
s
)
.
sum
source
@[simp]
theorem
Rat
.
cast_multiset_sum
{α :
Type
u_2}
[
DivisionRing
α
]
[
CharZero
α
]
(s :
Multiset
ℚ
)
:
↑
s
.
sum
=
(
Multiset.map
Rat.cast
s
)
.
sum
source
@[simp]
theorem
Rat
.
cast_sum
{ι :
Type
u_1}
{α :
Type
u_2}
[
DivisionRing
α
]
[
CharZero
α
]
(s :
Finset
ι
)
(f :
ι
→
ℚ
)
:
↑
(∑
i
∈
s
,
f
i
)
=
∑
i
∈
s
,
↑
(
f
i
)
source
@[simp]
theorem
Rat
.
cast_list_prod
{α :
Type
u_2}
[
DivisionRing
α
]
[
CharZero
α
]
(s :
List
ℚ
)
:
↑
s
.
prod
=
(
List.map
Rat.cast
s
)
.
prod
source
@[simp]
theorem
Rat
.
cast_multiset_prod
{α :
Type
u_2}
[
Field
α
]
[
CharZero
α
]
(s :
Multiset
ℚ
)
:
↑
s
.
prod
=
(
Multiset.map
Rat.cast
s
)
.
prod
source
@[simp]
theorem
Rat
.
cast_prod
{ι :
Type
u_1}
{α :
Type
u_2}
[
Field
α
]
[
CharZero
α
]
(s :
Finset
ι
)
(f :
ι
→
ℚ
)
:
↑
(∏
i
∈
s
,
f
i
)
=
∏
i
∈
s
,
↑
(
f
i
)