text/ncat.tex
changeset 855 3e1d7e7f8dfd
parent 853 870d6fac5420
child 857 4ad6325c7c7d
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854:1e4bb652812d 855:3e1d7e7f8dfd
  2576 (a) supported away from $E$, or (b) modify $E$ in the simple manner described above.
  2576 (a) supported away from $E$, or (b) modify $E$ in the simple manner described above.
  2577 \end{proof}
  2577 \end{proof}
  2578 
  2578 
  2579 It follows from the lemma that we can construct an isomorphism
  2579 It follows from the lemma that we can construct an isomorphism
  2580 between $\cS(X; c; E)$ and $\cS(X; c; E')$ for any pair $E$, $E'$.
  2580 between $\cS(X; c; E)$ and $\cS(X; c; E')$ for any pair $E$, $E'$.
  2581 This construction involves on a choice of simple ``moves" (as above) to transform
  2581 This construction involves a choice of simple ``moves" (as above) to transform
  2582 $E$ to $E'$.
  2582 $E$ to $E'$.
  2583 We must now show that the isomorphism does not depend on this choice.
  2583 We must now show that the isomorphism does not depend on this choice.
  2584 We will show below that it suffice to check two ``movie moves".
  2584 We will show below that it suffices to check two ``movie moves".
  2585 
  2585 
  2586 The first movie move is to push $E$ across an $n$-ball $B$ as above, then push it back.
  2586 The first movie move is to push $E$ across an $n$-ball $B$ as above, then push it back.
  2587 The result is equivalent to doing nothing.
  2587 The result is equivalent to doing nothing.
  2588 As we remarked above, the isomorphisms corresponding to these two pushes are mutually
  2588 As we remarked above, the isomorphisms corresponding to these two pushes are mutually
  2589 inverse, so we have invariance under this movie move.
  2589 inverse, so we have invariance under this movie move.
  2673 product for $B_1\cup B_2$ with the inner products for $B_1$ and $B_2$.
  2673 product for $B_1\cup B_2$ with the inner products for $B_1$ and $B_2$.
  2674 
  2674 
  2675 %The third movie move could be called ``locality" or ``disjoint commutativity".
  2675 %The third movie move could be called ``locality" or ``disjoint commutativity".
  2676 %\nn{...}
  2676 %\nn{...}
  2677 
  2677 
  2678 If $n\ge 2$, these two movie move suffice:
  2678 If $n\ge 2$, these two movie moves suffice:
  2679 
  2679 
  2680 \begin{lem}
  2680 \begin{lem}
  2681 Assume $n\ge 2$ and fix $E$ and $E'$ as above.
  2681 Assume $n\ge 2$ and fix $E$ and $E'$ as above.
  2682 Then any two sequences of elementary moves connecting $E$ to $E'$
  2682 Then any two sequences of elementary moves connecting $E$ to $E'$
  2683 are related by a sequence of the two movie moves defined above.
  2683 are related by a sequence of the two movie moves defined above.
  2694 (b) have boundaries corresponding to the two movie moves above.
  2694 (b) have boundaries corresponding to the two movie moves above.
  2695 Finally, observe that the space of $E$'s is simply connected.
  2695 Finally, observe that the space of $E$'s is simply connected.
  2696 (This fails for $n=1$.)
  2696 (This fails for $n=1$.)
  2697 \end{proof}
  2697 \end{proof}
  2698 
  2698 
  2699 For $n=1$ we have to check an additional ``global" relations corresponding to 
  2699 For $n=1$ we have to check an additional ``global" relation corresponding to 
  2700 rotating the 0-sphere $E$ around the 1-sphere $\bd X$.
  2700 rotating the 0-sphere $E$ around the 1-sphere $\bd X$.
  2701 But if $n=1$, then we are in the case of ordinary algebroids and bimodules,
  2701 But if $n=1$, then we are in the case of ordinary algebroids and bimodules,
  2702 and this is just the well-known ``Frobenius reciprocity" result for bimodules \cite{MR1424954}.
  2702 and this is just the well-known ``Frobenius reciprocity" result for bimodules \cite{MR1424954}.
  2703 
  2703 
  2704 \medskip
  2704 \medskip