Lemmas on infinite sums and products in topological monoids #
This file contains many simple lemmas on tsum
, HasSum
etc, which are placed here in order to
keep the basic file of definitions as short as possible.
Results requiring a group (rather than monoid) structure on the target should go in Group.lean
.
Constant zero function has sum 0
Constant one function has product 1
A special case of Summable.map_iff_of_leftInverse
for convenience
"A special case of Multipliable.map_iff_of_leftInverse
for convenience"
Version of HasSum.update
for AddCommMonoid
rather than AddCommGroup
.
Rather than showing that f.update
has a specific sum in terms of HasSum
,
it gives a relationship between the sums of f
and f.update
given that both exist.
Version of HasProd.update
for CommMonoid
rather than CommGroup
.
Rather than showing that f.update
has a specific product in terms of HasProd
,
it gives a relationship between the products of f
and f.update
given that both exist.
Version of hasSum_ite_sub_hasSum
for AddCommMonoid
rather than AddCommGroup
.
Rather than showing that the ite
expression has a specific sum in terms of HasSum
,
it gives a relationship between the sums of f
and ite (n = b) 0 (f n)
given that both exist.
Version of hasProd_ite_div_hasProd
for CommMonoid
rather than CommGroup
.
Rather than showing that the ite
expression has a specific product in terms of HasProd
, it gives
a relationship between the products of f
and ite (n = b) 0 (f n)
given that both exist.
If f b = 0
for all b ∈ t
, then the sum of f a
with a ∈ s
is the same as the
sum of f a
with a ∈ s ∖ t
.
If f b = 1
for all b ∈ t
, then the product of f a
with a ∈ s
is the same as the
product of f a
with a ∈ s ∖ t
.
If f b = 0
, then the sum of f a
with a ∈ s
is the same as the sum of f a
for a ∈ s ∖ {b}
.
If f b = 1
, then the product of f a
with a ∈ s
is the same as the product of f a
for
a ∈ s ∖ {b}
.
Version of tsum_eq_add_tsum_ite
for AddCommMonoid
rather than AddCommGroup
.
Requires a different convergence assumption involving Function.update
.
Version of tprod_eq_mul_tprod_ite
for CommMonoid
rather than CommGroup
.
Requires a different convergence assumption involving Function.update
.