Continuous monoid action #
In this file we define class ContinuousSMul
. We say ContinuousSMul M X
if M
acts on X
and
the map (c, x) ↦ c • x
is continuous on M × X
. We reuse this class for topological
(semi)modules, vector spaces and algebras.
Main definitions #
ContinuousSMul M X
: typeclass saying that the map(c, x) ↦ c • x
is continuous onM × X
;Units.continuousSMul
: scalar multiplication byMˣ
is continuous when scalar multiplication byM
is continuous. This allowsHomeomorph.smul
to be used with on monoids withG = Mˣ
.
-- Porting note: These have all moved
Homeomorph.smul_of_ne_zero
: if a group with zeroG₀
(e.g., a field) acts onX
andc : G₀
is a nonzero element ofG₀
, then scalar multiplication byc
is a homeomorphism ofX
;Homeomorph.smul
: scalar multiplication by an element of a groupG
acting onX
is a homeomorphism ofX
.
Main results #
Besides homeomorphisms mentioned above, in this file we provide lemmas like Continuous.smul
or Filter.Tendsto.smul
that provide dot-syntax access to ContinuousSMul
.
- continuous_smul : Continuous fun p => p.fst • p.snd
The scalar multiplication
(•)
is continuous.
Class ContinuousSMul M X
says that the scalar multiplication (•) : M → X → X
is continuous in both arguments. We use the same class for all kinds of multiplicative actions,
including (semi)modules and algebras.
Instances
- continuous_vadd : Continuous fun p => p.fst +ᵥ p.snd
The additive action
(+ᵥ)
is continuous.
Class ContinuousVAdd M X
says that the additive action (+ᵥ) : M → X → X
is continuous in both arguments. We use the same class for all kinds of additive actions,
including (semi)modules and algebras.
Instances
If an additive action is central, then its right action is continuous when its left action is.
If a scalar action is central, then its right action is continuous when its left action is.
An AddTorsor
for a connected space is a connected space. This is not an instance because
it loops for a group as a torsor over itself.