Embeddings in Euclidean space: plan and convention

From Manifold Atlas
(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
+
#REDIRECT [[Embeddings in Euclidean space: an introduction to their classification#Notation_and_conventions]]
{{Authors|Askopenkov}}
{{Authors|Askopenkov}}
== Introduction ==
== Introduction ==

Latest revision as of 01:42, 8 April 2020

  1. REDIRECT Embeddings in Euclidean space: an introduction to their classification#Notation_and_conventions

The user responsible for this page is Askopenkov. No other user may edit this page at present.

Contents

1 Introduction

This page gives references to pages on the classification of embeddings, and introduces notation and conventions used there.

2 References to pages on the classification of embeddings

Here is the introductory article:

Below we list references to information about the classification of embeddings of manifolds into Euclidean space.

The first list is structured by the dimension of the source manifold and the target Euclidean space:

Information structured by the `complexity' of the source manifold:

For more information see e.g. [Skopenkov2006].

3 Notation and conventions

The following notations and conventions will be used in some other pages about embeddings, including those listed in \S2.

For a manifold N let E^m_D(N) or E^m_{PL}(N) denote the set of smooth or piecewise-linear (PL) embeddings N\to S^m up to smooth or PL isotopy. If the category is omitted, then the result holds (or a definition or a construction is given) in both categories.

The sources of all embeddings are assumed to be compact.

Let B^n be a closed n-ball in a closed connected n-manifold N. Denote N_0:=Cl(N-B^n).

Let \varepsilon(k):=1-(-1)^k be 0 for k even and 2 for k odd, so that \Zz_{\varepsilon(k)} is \Zz for k even and \Zz_2 for k odd.

Denote by V_{m,n} the Stiefel manifold of orthonormal n-frames in \Rr^m.

We omit \Zz-coefficients from the notation of (co)homology groups.

For a manifold P with boundary \partial P denote H_s(P,\partial):=H_s(P,\partial P).

A closed manifold N is called homologically k-connected, if N is connected and H_i(N)=0 for every i=1,\dots,k. This condition is equivalent to \tilde H_i(N)=0 for each i=0,\dots,k, where \tilde H_i are reduced homology groups. A pair (N,\partial N) is called homologically k-connected, if H_i(N,\partial)=0 for every i=0,\dots,k.

The self-intersection set of a map f:X\to Y is \Sigma(f):=\{x\in X\ :\ |f^{-1}fx|>1\}.

For a smooth embedding f:N\to\Rr^m denote by

  • C_f the closure of the complement in S^m\supset\Rr^m to a tight enough tubular neighborhood of f(N) and
  • \nu_f:\partial C_f\to N the restriction of the linear normal bundle of f to the subspace of unit length vectors identified with \partial C_f.
  • \widehat A_f:H_s(N)\to H_{s+m-n-1}(C) and A_f:H_s(N)\to H_{s+1}(C,\partial) the homological Alexander duality isomorphisms, see the well-known Alexander Duality Lemmas of [Skopenkov2008], [Skopenkov2005].

4 References

$ for $k$ even and $ for $k$ odd, so that $\Zz_{\varepsilon(k)}$ is $\Zz$ for $k$ even and $\Zz_2$ for $k$ odd. Denote by $V_{m,n}$ the Stiefel manifold of orthonormal $n$-frames in $\Rr^m$. We omit $\Zz$-coefficients from the notation of (co)homology groups. For a manifold $P$ with boundary $\partial P$ denote $H_s(P,\partial):=H_s(P,\partial P)$. A closed manifold $N$ is called ''homologically $k$-connected'', if $N$ is connected and $H_i(N)=0$ for every $i=1,\dots,k$. This condition is equivalent to $\tilde H_i(N)=0$ for each $i=0,\dots,k$, where $\tilde H_i$ are reduced homology groups. A pair $(N,\partial N)$ is called ''homologically $k$-connected'', if $H_i(N,\partial)=0$ for every $i=0,\dots,k$. The ''self-intersection set'' of a map $f:X\to Y$ is $\Sigma(f):=\{x\in X\ :\ |f^{-1}fx|>1\}.$ For a smooth embedding $f:N\to\Rr^m$ denote by * $C_f$ the closure of the complement in $S^m\supset\Rr^m$ to a tight enough tubular neighborhood of $f(N)$ and * $\nu_f:\partial C_f\to N$ the restriction of the linear normal bundle of $f$ to the subspace of unit length vectors identified with $\partial C_f$. * $\widehat A_f:H_s(N)\to H_{s+m-n-1}(C)$ and $A_f:H_s(N)\to H_{s+1}(C,\partial)$ the homological Alexander duality isomorphisms, see the well-known Alexander Duality Lemmas of \cite{Skopenkov2008}, \cite{Skopenkov2005}. == References == {{#RefList:}} [[Category:Theory]] [[Category:Manifolds]] [[Category:Embeddings of manifolds]]\S2.

For a manifold N let E^m_D(N) or E^m_{PL}(N) denote the set of smooth or piecewise-linear (PL) embeddings N\to S^m up to smooth or PL isotopy. If the category is omitted, then the result holds (or a definition or a construction is given) in both categories.

The sources of all embeddings are assumed to be compact.

Let B^n be a closed n-ball in a closed connected n-manifold N. Denote N_0:=Cl(N-B^n).

Let \varepsilon(k):=1-(-1)^k be 0 for k even and 2 for k odd, so that \Zz_{\varepsilon(k)} is \Zz for k even and \Zz_2 for k odd.

Denote by V_{m,n} the Stiefel manifold of orthonormal n-frames in \Rr^m.

We omit \Zz-coefficients from the notation of (co)homology groups.

For a manifold P with boundary \partial P denote H_s(P,\partial):=H_s(P,\partial P).

A closed manifold N is called homologically k-connected, if N is connected and H_i(N)=0 for every i=1,\dots,k. This condition is equivalent to \tilde H_i(N)=0 for each i=0,\dots,k, where \tilde H_i are reduced homology groups. A pair (N,\partial N) is called homologically k-connected, if H_i(N,\partial)=0 for every i=0,\dots,k.

The self-intersection set of a map f:X\to Y is \Sigma(f):=\{x\in X\ :\ |f^{-1}fx|>1\}.

For a smooth embedding f:N\to\Rr^m denote by

  • C_f the closure of the complement in S^m\supset\Rr^m to a tight enough tubular neighborhood of f(N) and
  • \nu_f:\partial C_f\to N the restriction of the linear normal bundle of f to the subspace of unit length vectors identified with \partial C_f.
  • \widehat A_f:H_s(N)\to H_{s+m-n-1}(C) and A_f:H_s(N)\to H_{s+1}(C,\partial) the homological Alexander duality isomorphisms, see the well-known Alexander Duality Lemmas of [Skopenkov2008], [Skopenkov2005].

4 References

Personal tools
Namespaces
Variants
Actions
Navigation
Interaction
Toolbox