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61.
二阶离散Hamiltonian系统的多重周期解 总被引:2,自引:0,他引:2
利用变分原理和Clark定理,研究了带参数的二阶离散Hamiltonian系统的多重周期解,得到了此类方程周期解个数的下界估计. 相似文献
62.
ZHAO Xu''''an GAO Hongzhu & QIU Huaidong LMAM School of Mathematics Science Beijing Normal University Beijing China 《中国科学A辑(英文版)》2006,49(9)
There are three key ingredients in the study of the minimal genus problem for rational surfaces CP2#nCP2: the generalized adjunction formula, the action of the orthogonal group of the Lorentz space and the geometric construction. In this paper, we prove the uniqueness of the standard form (see Definition 1.1 and Theorem 1.1) of a 2-dimensional homology class under the action of the subgroup of the Lorentz orthogonal group that is realized by the diffeomorphisms of CP2#nCP2.Using the geometric construction, we determine the minimal genera of some classes (see Theorem 1.2). 相似文献
63.
1.IntroductionThernchmumgenusl7M(G),ofacormectedgraphG~(V,E)isthem~amongthegenera,amongwhichGhasacellularembeddingonaspherewithkhandles.SinceanyembeddingofGhasatleastonefaCe,byEulerpolyhedralequation,itcanbeobtainedthatwhereP(G)=IE(G)I--IV(G)l IisthecyclerankofG.AgraphGiscalledop-imbeddableif7M(C)=Lop]exactly.Kund.[1]provedthatthereareatleasttWOedge-disjointspanningtreesinGifGis4-edgecormected.LiuandXuongcharacterizedtheuptheeddabilityofgraphsasinthefollowing.Theorem1.112'31.Acorm… 相似文献
64.
I. A. Bikchantaev 《Mathematical Notes》2000,67(1):20-28
LetR be the Riemann surface of the functionu(z) specified by the equationu
n=P(z) withn ε ℕ,n ≥ 2, andz ε ℂ, whereP(z) is an entire function with infinitely many simple zeros. OnR, the Riemann boundary-value problem for an arbitrary piecewise smooth contour Γ is considered. Necessary and sufficient conditions
for its solvability are obtained, and its explicit solution is constructed.
Translated fromMatematicheskie Zametki, Vol. 67, No. 1, pp. 25–35, January, 2000. 相似文献
65.
Noriaki Kamiya 《代数通讯》2013,41(6):1833-1844
It is the object of this paper to investigate the Peirce decomposition for Freudenthal-Kantor triple systems, by making use of the concept of anti-derivation of the triple systems. 相似文献
66.
A well‐known conjecture in topological graph theory says that the genus distribution of every graph is log‐concave. In this paper, the genus distribution of the circular ladder is re‐derived, using overlap matrices and Chebyshev polynomials, which facilitates proof that this genus distribution is log‐concave. 相似文献
67.
In the paper, we prove that for every integer n ≥ 1, there exists a Petersen power Pn with nonorientable genus and Euler genus precisely n, which improves the upper bound of Mohar and Vodopivec's result [J. Graph Theory, 67, 1–8(2011)] that for every integer k(2 ≤ k ≤ n- 1), a Petersen power Pnexists with nonorientable genus and Euler genus precisely k. 相似文献
68.
In this paper a method is given to calculate the explicit expressions of embedding genus distribution for ladder type graphs
and cross type graphs. As an example, we refind the genus distribution of the graph J
n
which is the first class of graphs studied for genus distribution where its genus depends on n.
This work was supported National Natural Science Foundation of China (Grant Nos. 10571013, 60433050) and the State Key Development
Program of Basic Research of China (Grant No. 2004CB318004) 相似文献
69.
利用图的直径和围长来研究图的最大亏格的下界,得到了如下结果:设G是直径为d的简单图,若G的围长不小于d(其中d为不小于3的整数),则ξ(G)≤2,即γM(G)≥1/2β(G)-1.而且,在这种意义下,所得到的界是最好的. 相似文献
70.
Ian Agol Joel Hass William Thurston 《Transactions of the American Mathematical Society》2006,358(9):3821-3850
We show that the problem of deciding whether a polygonal knot in a closed three-dimensional manifold bounds a surface of genus at most is NP-complete. We also show that the problem of deciding whether a curve in a PL manifold bounds a surface of area less than a given constant is NP-hard.