Mikhail SODIN
Mikhail SODIN
Mikhail SODIN
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✬<br />
Part V: Steps in the proof of Theorem I<br />
Step 1: Some integral geometry<br />
Notation: N(u, r; F ) the number of connected components of Z(F )<br />
contained in the open ball B(u, r)<br />
¯N(u, r; F ) the number of connected components of Z(F ) that intersect<br />
the closed ball B(u, r)<br />
Lemma: For 0 < r < R < ∞,<br />
<br />
<br />
N(u, r; F )<br />
du ≤ N(R; F ) ≤<br />
volB(r)<br />
✫<br />
B(R−r)<br />
We apply this with 1 ≪ r ≪ R.<br />
B(R+r)<br />
¯N(u, r; F )<br />
volB(r) du<br />
Notation: (τvF )(u)=F (u + v) (translation). Then N(u, r; F )=N(r; τuF )<br />
Observe: ¯ N(r; F ) − N(r; F ) ≤ N(r; F ) def<br />
= # of critical pts of F ∂B(r)<br />
21<br />
to be continued on the next slide<br />
✩<br />
✪