Some Inequalities for Submanifolds in Cosymplectic Space Forms

For submanifolds in a cosymplectic space form tangent to the structure vector field ξ, two important inequalities with Ricci curvature, scalar curvature and the squared mean curvature are obtained. These results are also applied to get corresponding consequences for anti-invariant submanifolds.

关于Poisson群胚的结构

令（ΓP,α，β）是Poisson群胚．如果它的每个α-纤维与β-纤维至多交于一点，则Γ在任一点x的特征分布有直和分解△（x）=△α（x）+△β（x），其中△α（x）Txα－1（u），△β（x）Txβ-1（u）且它们都是△（x）的辛子空间．由此得到辛叶Sx的辛子流形S和S，使在映射α之下，S辛微分同胚于P中辛叶Su，在映射β之下，S反辛微分同胚于P中辛叶Sv（定理4和5）．对于一般的Poisson群胚，也可得到类似的S和S，它们差一局部辛微分同胚是唯一确定的（定理6）．把以上结果用于辛群胚，还可得到一些更具体的性质（定理7及其推论）．

ON THE SYMPLECTIC REDUCTIONS

A symplectic reduction method for symplectic G-spaces is given in this paper without using the existence of momentum mappings. By a method similar to the above one, the arthors give a symplectic reduction method for the Poisson action of Poisson Lie groups on symplectic manifolds, also without using the existence of momentum mappings. The symplectic reduction method for momentum mappings is thus a special case of the above results.