Extended charts in smooth manifolds #
In a C^n manifold with corners with the model I on (E, H), the charts take values in the
model space H. However, we also need to use extended charts taking values in the model vector
space E. These extended charts are not OpenPartialHomeomorph as the target is not open in E
in general, but we can still register them as PartialEquiv.
Main definitions #
OpenPartialHomeomorph.extend: compose an open partial homeomorphism intoHwith the modelI, to obtain aPartialEquivintoE. Extended charts are an example of this.extChartAt I x: the extended chart atx, obtained by composing thechartAt H xwithI. Since the target is in general not open, this is not an open partial homeomorphism in general, but we register them asPartialEquivs.
Main results #
contDiffOn_extend_coord_change: iffandf'lie in the maximal atlas onM,f.extend I โ (f'.extend I).symmis continuous on its sourcecontDiffOn_ext_coord_change: forx x : M, the coordinate change(extChartAt I x').symm โซ extChartAt I xis continuous on its sourceManifold.locallyCompact_of_finiteDimensional: a finite-dimensional manifold modelled on a locally compact field (such as โ, โ or thep-adic numbers) is locally compactLocallyCompactSpace.of_locallyCompact_manifold: a locally compact manifold must be modelled on a locally compact space.FiniteDimensional.of_locallyCompact_manifold: a locally compact manifolds must be modelled on a finite-dimensional space
Given a chart f on a manifold with corners, f.extend I is the extended chart to the model
vector space.
Equations
- f.extend I = f.trans I.toPartialEquiv
Instances For
Variant of f.extend_left_inv I, stated in terms of images.
Alias of OpenPartialHomeomorph.extend_image_nhds_mem_nhds_of_boundaryless.
Alias of OpenPartialHomeomorph.extend_image_nhds_mem_nhds_of_mem_interior_range.
If y โ f.target and I y โ interior (range I),
then I y is an interior point of (I โ f).target.
If s โ f.source and g x โ f'.source whenever x โ s, then g is continuous on s if and
only if g written in charts f.extend I and f'.extend I' is continuous on f.extend I '' s.
Technical lemma ensuring that the preimage under an extended chart of a neighborhood of a point in the source is a neighborhood of the preimage, within a set.
Technical lemma to rewrite suitably the preimage of an intersection under an extended chart, to bring it into a convenient form to apply derivative lemmas.
The preferred extended chart on a manifold with corners around a point x, from a neighborhood
of x to the model vector space.
Equations
- extChartAt I x = (chartAt H x).extend I
Instances For
Alias of extChartAt_image_nhds_mem_nhds_of_mem_interior_range.
If we're boundaryless, extChartAt has open target
If we're boundaryless, (extChartAt I x).target is a neighborhood of the key point
If we're boundaryless, (extChartAt I x).target is a neighborhood of any of its points
Around the image of a point in the source, the neighborhoods are the same
within (extChartAt I x).target and within range I.
Around a point in the target, the neighborhoods are the same within (extChartAt I x).target
and within range I.
Around the image of the base point, the neighborhoods are the same
within (extChartAt I x).target and within range I.
Around the image of a point in the source, (extChartAt I x).target and range I
coincide locally.
Around a point in the target, (extChartAt I x).target and range I coincide locally.
Around the image of the base point, (extChartAt I x).target and range I coincide locally.
Technical lemma ensuring that the preimage under an extended chart of a neighborhood of a point in the source is a neighborhood of the preimage, within a set.
Technical lemma ensuring that the preimage under an extended chart of a neighborhood of the base point is a neighborhood of the preimage, within a set.
Technical lemma ensuring that the preimage under an extended chart of a neighborhood of a point is a neighborhood of the preimage.
Technical lemma to rewrite suitably the preimage of an intersection under an extended chart, to bring it into a convenient form to apply derivative lemmas.
We use the name ext_coord_change for (extChartAt I x').symm โซ extChartAt I x.
Conjugating a function to write it in the preferred charts around x.
The manifold derivative of f will just be the derivative of this conjugated function.
Equations
- writtenInExtChartAt I I' x f = โ(extChartAt I' (f x)) โ f โ โ(extChartAt I x).symm
Instances For
In the case of the manifold structure on a vector space, the extended charts are just the identity.
A finite-dimensional manifold modelled on a locally compact field
(such as โ, โ or the p-adic numbers) is locally compact.
A locally compact manifold must be modelled on a locally compact space.
Riesz's theorem applied to manifolds: a locally compact manifolds must be modelled on a
finite-dimensional space. This is the converse to Manifold.locallyCompact_of_finiteDimensional.