arXiv · math/9811113
S.P.Novikov developed an analog of the Morse theory for closed 1-forms. In this paper I suggest an analog of the Lusternik - Schnirelman theory for closed 1-forms.
Michael Farber. 1998-11-18. Lusternik-Schnirelman theory for closed 1-forms. https://arxiv.org/abs/math/9811113
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