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9 papers
Framed Morse functions on surfaces
E. A. Kudryavtseva,
D. A. Permyakov M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics
Abstract:
Let
$M$ be a smooth, compact, not necessarily orientable surface with (maybe empty) boundary, and let
$F$ be the space of Morse functions on
$M$ that are constant on each component of the boundary and have no critical points at the boundary. The notion of framing is defined for a Morse function
$f\in F$. In the case of an orientable surface
$M$ this is a closed 1-form
$\alpha$ on
$M$ with punctures at the critical points of local minimum and maximum of
$f$ such that in a neighbourhood of each critical point the pair
$(f,\alpha)$ has a canonical form in a suitable local coordinate chart and the 2-form
$df\wedge\alpha$ does not vanish on
$M$ punctured at the critical points and defines there a positive orientation. Each Morse function on
$M$ is shown to have a framing, and the space
$F$ endowed with the
$C^\infty$-topology is homotopy equivalent
to the space
$\mathbb F$ of framed Morse functions. The results obtained make it possible to reduce the problem of describing the homotopy type of
$F$ to the simpler problem of finding the homotopy type of
$\mathbb F$. As a solution of the latter, an analogue of the parametric
$h$-principle is stated for the space
$\mathbb F$.
Bibliography: 41 titles.
Keywords:
Morse functions, framed Morse functions, equivalence of functions, compact surface, $C^\infty$-topology.
UDC:
515.164.174+
515.164.22+
515.122.55
MSC: 57R45,
58D15 Received: 18.03.2009 and 02.07.2009
DOI:
10.4213/sm7557