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 • xis continuous on- M × X;
- Units.continuousSMul: scalar multiplication by- Mˣis continuous when scalar multiplication by- Mis continuous. This allows- Homeomorph.smulto be used with on monoids with- G = Mˣ.
-- Porting note: These have all moved
- Homeomorph.smul_of_ne_zero: if a group with zero- G₀(e.g., a field) acts on- Xand- c : G₀is a nonzero element of- G₀, then scalar multiplication by- cis a homeomorphism of- X;
- Homeomorph.smul: scalar multiplication by an element of a group- Gacting on- Xis a homeomorphism of- X.
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.sndThe 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.sndThe 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.