text/basic_properties.tex
changeset 492 833bd74143a4
parent 486 354750591746
child 506 4a23163843a9
equal deleted inserted replaced
491:045e01f63729 492:833bd74143a4
    85 $r$ be the restriction of $b$ to $X\setminus S$.
    85 $r$ be the restriction of $b$ to $X\setminus S$.
    86 Note that $S$ is a disjoint union of balls.
    86 Note that $S$ is a disjoint union of balls.
    87 Assign to $b$ the acyclic (in positive degrees) subcomplex $T(b) \deq r\bullet\bc_*(S)$.
    87 Assign to $b$ the acyclic (in positive degrees) subcomplex $T(b) \deq r\bullet\bc_*(S)$.
    88 Note that if a diagram $b'$ is part of $\bd b$ then $T(B') \sub T(b)$.
    88 Note that if a diagram $b'$ is part of $\bd b$ then $T(B') \sub T(b)$.
    89 Both $f$ and the identity are compatible with $T$ (in the sense of acyclic models), 
    89 Both $f$ and the identity are compatible with $T$ (in the sense of acyclic models), 
    90 so $f$ and the identity map are homotopic. \nn{We should actually have a section with a definition of ``compatible" and this statement as a lemma}
    90 so $f$ and the identity map are homotopic. \nn{We should actually have a section \S \ref{sec:moam} with a definition of ``compatible" and this statement as a lemma}
    91 \end{proof}
    91 \end{proof}
    92 
    92 
    93 For the next proposition we will temporarily restore $n$-manifold boundary
    93 For the next proposition we will temporarily restore $n$-manifold boundary
    94 conditions to the notation. Let $X$ be an $n$-manifold, with $\bd X = Y \cup Y \cup Z$.
    94 conditions to the notation. Let $X$ be an $n$-manifold, with $\bd X = Y \cup Y \cup Z$.
    95 Gluing the two copies of $Y$ together yields an $n$-manifold $X\sgl$
    95 Gluing the two copies of $Y$ together yields an $n$-manifold $X\sgl$