Monotone Lagrange submanifolds of linear spaces and the Maslov class in cotangent bundles
Monotone Lagrange submanifolds of linear spaces and the Maslov class in cotangent bundles
复制标题
线性空间的单调拉格朗日子流形和余切丛中的 Maslov 类
DOI:
10.1007/bf02571385
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发表时间:
1991
影响因子:
0.8
通讯作者:
L. Polterovich
中科院分区:
文献类型:
--
作者:
L. Polterovich
1 We consider below two kinds of symplectic manifolds, the linear complex space•" and the contangent bundle T* W. Each of them is endowed with the standard symplectic structure, co. It's well known that co is exact:~ o= d r. Denote one of these spaces by V. For a Lagrange immersion f: W--* Vsetm (f)=[f*~]~ H 1 (W; R) and let#(f)~ H 1 (W; Z) be the Maslov class. Denote by m (f) the non-negative generator of the subgroup#(f)(H1 (W; Z))~ Z. 2 In the present paper, we study the invariant m (f) for Lagrange embeddings f: W--* V. Our main result is that re (f)= 0 if W= S"~•...• T~, V= T* W and f is an exact Lagrange embedding (see Theor. 2 and Remarks 3 5 below). For the case W= T this result was obtained by F. Lalonde and J.-C. Sikorav [LS] and by C. Viterbo (the final version of IV]). Their methods are different, however, they are both based on the following result by C. Viterbo IV]: 0< m (f)< n+ 1 for every Lagrange embedding f: T"--. C". Mention that this result partially proves the hypothesis by M. Audin [A2] stating that m (f)= 2 for any such embedding. For the proof of this estimate C. Viterbo uses an approach based on the study of closed orbits of some special Hamiltonian system associated to an embedded Lagrange torus in I12". Our method is the following. First we prove that O< m (f)< n+ 1 for monotone Lagrange embeddings W~ 1~"(see the definition, Theor. 1 and Remark 2 below). The proof is based on Gromov's theory of pseudo-holomorphic curves [-G]. Afterwards using the arguments by F. Lalonde and J.-C. Sikorav we conclude that the Maslov class is trivial for some exact Lagrange submanifolds of the contangent bundles. Mention that the pseudo-holomorphic curves approach was used in lP] for study of the Maslov class of Lagrange surfaces. The results of this paper were announced at the Moscow Seminar of the Singularities Theory under the guidance of VI Arnold in autumn 1989. I am deeply grateful to AB Givental and KM Khanin for useful discussions, and to J.-C. Sikorav for reading the manuscript and improving remarks.Definition. A Lagrange immersion f: W~ 112" is called monotone (cf. IF2]) if