text/ncat.tex
changeset 211 ef127ac682bd
parent 209 0e71da01b195
child 218 1acb5f508cf6
equal deleted inserted replaced
210:5200a0eac737 211:ef127ac682bd
   570 We can modify Example \ref{ex:maps-to-a-space} above to define the fundamental $A_\infty$ $n$-category $\pi^\infty_{\le n}(T)$ of a topological space $T$.
   570 We can modify Example \ref{ex:maps-to-a-space} above to define the fundamental $A_\infty$ $n$-category $\pi^\infty_{\le n}(T)$ of a topological space $T$.
   571 For $k$-balls and $k$-spheres $X$, with $k < n$, the sets $\pi^\infty_{\leq n}(T)(X)$ are just $\Maps{X \to T}$.
   571 For $k$-balls and $k$-spheres $X$, with $k < n$, the sets $\pi^\infty_{\leq n}(T)(X)$ are just $\Maps{X \to T}$.
   572 Define $\pi^\infty_{\leq n}(T)(X; c)$ for an $n$-ball $X$ and $c \in \pi^\infty_{\leq n}(T)(\bdy X)$ to be the chain complex
   572 Define $\pi^\infty_{\leq n}(T)(X; c)$ for an $n$-ball $X$ and $c \in \pi^\infty_{\leq n}(T)(\bdy X)$ to be the chain complex
   573 $$C_*(\Maps_c(X\times F \to T)),$$ where $\Maps_c$ denotes continuous maps restricting to $c$ on the boundary,
   573 $$C_*(\Maps_c(X\times F \to T)),$$ where $\Maps_c$ denotes continuous maps restricting to $c$ on the boundary,
   574 and $C_*$ denotes singular chains.
   574 and $C_*$ denotes singular chains.
       
   575 \nn{maybe should also mention version where we enrich over spaces rather than chain complexes}
   575 \end{example}
   576 \end{example}
   576 
   577 
   577 See ??? below, recovering $C_*(\Maps{M \to T})$ as (up to homotopy) the blob complex of $M$ with coefficients in $\pi^\infty_{\le n}(T)$.
   578 See \ref{thm:map-recon} below, recovering $C_*(\Maps{M \to T})$ as (up to homotopy) the blob complex of $M$ with coefficients in $\pi^\infty_{\le n}(T)$.
   578 
   579 
   579 \begin{example}[Blob complexes of balls (with a fiber)]
   580 \begin{example}[Blob complexes of balls (with a fiber)]
   580 \rm
   581 \rm
   581 \label{ex:blob-complexes-of-balls}
   582 \label{ex:blob-complexes-of-balls}
   582 Fix an $m$-dimensional manifold $F$.
   583 Fix an $m$-dimensional manifold $F$.