text/basic_properties.tex
changeset 141 e1d24be683bb
parent 100 c5a43be00ed4
child 221 77b0cdeb0fcd
equal deleted inserted replaced
140:e0b304e6b975 141:e1d24be683bb
    25 
    25 
    26 Suppose that for all $c \in \cC(\bd B^n)$
    26 Suppose that for all $c \in \cC(\bd B^n)$
    27 we have a splitting $s: H_0(\bc_*(B^n, c)) \to \bc_0(B^n; c)$
    27 we have a splitting $s: H_0(\bc_*(B^n, c)) \to \bc_0(B^n; c)$
    28 of the quotient map
    28 of the quotient map
    29 $p: \bc_0(B^n; c) \to H_0(\bc_*(B^n, c))$.
    29 $p: \bc_0(B^n; c) \to H_0(\bc_*(B^n, c))$.
    30 For example, this is always the case if you coefficient ring is a field.
    30 For example, this is always the case if the coefficient ring is a field.
    31 Then
    31 Then
    32 \begin{prop} \label{bcontract}
    32 \begin{prop} \label{bcontract}
    33 For all $c \in \cC(\bd B^n)$ the natural map $p: \bc_*(B^n, c) \to H_0(\bc_*(B^n, c))$
    33 For all $c \in \cC(\bd B^n)$ the natural map $p: \bc_*(B^n, c) \to H_0(\bc_*(B^n, c))$
    34 is a chain homotopy equivalence
    34 is a chain homotopy equivalence
    35 with inverse $s: H_0(\bc_*(B^n, c)) \to \bc_*(B^n; c)$.
    35 with inverse $s: H_0(\bc_*(B^n, c)) \to \bc_*(B^n; c)$.
    64 \end{prop}
    64 \end{prop}
    65 
    65 
    66 
    66 
    67 \begin{prop}
    67 \begin{prop}
    68 For fixed fields ($n$-cat), $\bc_*$ is a functor from the category
    68 For fixed fields ($n$-cat), $\bc_*$ is a functor from the category
    69 of $n$-manifolds and diffeomorphisms to the category of chain complexes and
    69 of $n$-manifolds and homeomorphisms to the category of chain complexes and
    70 (chain map) isomorphisms.
    70 (chain map) isomorphisms.
    71 \qed
    71 \qed
    72 \end{prop}
    72 \end{prop}
    73 
    73 
    74 In particular,
    74 In particular,
    75 \begin{prop}  \label{diff0prop}
    75 \begin{prop}  \label{diff0prop}
    76 There is an action of $\Diff(X)$ on $\bc_*(X)$.
    76 There is an action of $\Homeo(X)$ on $\bc_*(X)$.
    77 \qed
    77 \qed
    78 \end{prop}
    78 \end{prop}
    79 
    79 
    80 The above will be greatly strengthened in Section \ref{sec:evaluation}.
    80 The above will be greatly strengthened in Section \ref{sec:evaluation}.
    81 
    81 
   104 \end{prop}
   104 \end{prop}
   105 
   105 
   106 The above map is very far from being an isomorphism, even on homology.
   106 The above map is very far from being an isomorphism, even on homology.
   107 This will be fixed in Section \ref{sec:gluing} below.
   107 This will be fixed in Section \ref{sec:gluing} below.
   108 
   108 
   109 \nn{Next para not need, since we already use bullet = gluing notation above(?)}
   109 %\nn{Next para not needed, since we already use bullet = gluing notation above(?)}
   110 
   110 
   111 An instance of gluing we will encounter frequently below is where $X = X_1 \du X_2$
   111 %An instance of gluing we will encounter frequently below is where $X = X_1 \du X_2$
   112 and $X\sgl = X_1 \cup_Y X_2$.
   112 %and $X\sgl = X_1 \cup_Y X_2$.
   113 (Typically one of $X_1$ or $X_2$ is a disjoint union of balls.)
   113 %(Typically one of $X_1$ or $X_2$ is a disjoint union of balls.)
   114 For $x_i \in \bc_*(X_i)$, we introduce the notation
   114 %For $x_i \in \bc_*(X_i)$, we introduce the notation
   115 \eq{
   115 %\eq{
   116     x_1 \bullet x_2 \deq \gl(x_1 \otimes x_2) .
   116 %    x_1 \bullet x_2 \deq \gl(x_1 \otimes x_2) .
   117 }
   117 %}
   118 Note that we have resumed our habit of omitting boundary labels from the notation.
   118 %Note that we have resumed our habit of omitting boundary labels from the notation.
   119 
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