A subclass of Ockham algebras

Here we introduce a subclass of the class of Ockham algebras ( L ; f ) for which L satisfies the property that for every x ∈ L , there exists n ≥ 0 such that fn ( x ) and fn+1 ( x ) are complementary. We characterize the structure of the lattice of congruences on such an algebra ( L ; f ). We show that the lattice of compact congruences on L is a dual Stone lattice, and in particular, that the lattice Con L of congruences on L is boolean if and only if L is finite boolean. We also show that L is congruence coherent if and only if it is boolean. Finally, we give a sufficient and necessary condition to have the subdirectly irreducible chains.     

五种最优活法比鉴

受益宏观经济增长是登顶活力榜单的必要条件,凭借资本市场打开融资渠道同样非常重要。风光过后,上榜企业有四个方面挑战需要面对：一是宏观经济高增长是否持续;二是行业优势是否持续;三是现有盈利模式能否持续;四是能否适应业务结构与财别犬况的转变。     

时变种群扩散系统最优生育率控制的非线性问题

本文讨论了一类时变种群扩散系统最优生育率控制的非线性问题，证明了最优生育率控制的存在性，给出了控制为最优的必要条件及其最优性组，本结果可为种群扩散系统最优控制问题的实际研究提供物理理论基础。     

Banach空间上的左可逆算子的稳定性

主要讨论了Banach空间上左可逆算子在线性运算上的稳定性及一些摄动问题，并通过反例证明了对于Banach空间上的左可逆算子A和B，R（A）∩R（B）＝{0}不是λA＋B（λ∈C）为左可逆算子的必要条件。