On a complex manifold $(M,J)$, we interpret symplectic and pseudo-K\"ahler structures as forms with respect to which $J$ is, respectively, symmetric skew-symmetric. We classify on 4-dimensional Lie algebras. develop method for constructing hypersymplectic from the above data. This allows us obtain an example of structure 4-step nilmanifold.

an equitable risk allocation between contracting parties plays a vital role in enhancing the performance of the project. this research presents a new quantitative risk allocation approach by integrating fuzzy logic and bargaining game theory. owing to the imprecise and uncertain nature of players’ payoffs at different risk allocation strategies, fuzzy logic is implemented to determine the value...

This study is an investigation of fuzzy linear regression model for crisp/fuzzy input and fuzzy output data. A least absolutes deviations approach to construct such a model is developed by introducing and applying a new metric on the space of fuzzy numbers. The proposed approach, which can deal with both symmetric and non-symmetric fuzzy observations, is compared with several existing models by...

The robustness of the performance of a Bayesian network to shifts in its parameters can be studied with a sensitivity analysis. For reasons of computational efficiency such an analysis is often limited to studying shifts in only one or two parameters at a time. The concept of sensitivity value, an important notion in sensitivity analysis, captures the effect of local changes in a single paramet...

The descendant set desc(α) of a vertex α in a digraph D is the set of vertices which can be reached by a directed path from α. A subdigraph of D is finitely generated if it is the union of finitely many descendant sets and D is descendant-homogeneous if it is vertex transitive and any isomorphism between finitely generated subdigraphs extends to an automorphism. We consider connected descendant...

We consider a simple model to study the effects of the beam-beam force on the dynamics of colliding beams. We focus on the quadrupole modes of the coherent oscillation. The ingredients are: (1) linearized beam-beam kicks, (2) damping and noise due to synchrotron radiation, and (3) linear transport between beam-beam kicks. The dynamical variables are the 2nd-order moments of the canonical variab...

We present an order-theoretic approach to the study of countably infinite locally 2-arc-transitive bipartite graphs. Our approach is motivated by techniques developed by Warren and others during the study of cycle-free partial orders. We give several new families of previously unknown countably infinite locally-2-arc-transitive graphs, each family containing continuum many members. These exampl...

We construct a family of infinite, non-locally finite highly arc-transitive digraphs which do not have universal reachability relation and which omit special digraphs called ‘crowns’. Moreover, there is no homomorphism from any of our digraphs onto Z. The methods are adapted from [5] and [6].

Let D be a locally finite, connected, 1-arc transitive digraph. It is shown that the reachability relation is not universal in D provided that the stabilizer of an edge satisfies certain conditions which seem to be typical for highly arc transitive digraphs. As an implication, the reachability relation cannot be universal in highly arc transitive digraphs with prime inor out-degree. Two differe...