Actions of finite rank: weak rational ergodicity and partial rigidity

A simple proof of the fact that each rank-one infinite measure preserving (i.m.p.) transformation is subsequence weakly rationally ergodic is found. Some classes of funny rank-one i.m.p. actions of Abelian groups are shown to be subsequence weakly rationally ergodic. A constructive definition of finite funny rank for actions of arbitrary infinite countable groups is given. It is shown that the ergodic i.m.p. transformations of balanced finite funny rank are subsequence weakly rationally ergodic. It is shown that the ergodic probability preserving transformations of exact finite rank, the ergodic Bratteli–Vershik maps corresponding to the ‘consecutively ordered’ Bratteli diagrams of finite rank, some their generalizations and the ergodic interval exchange transformations are partially rigid.

Study on Stability of Arch Bridge by Finite Element Method

Arch is a structure suffers press mainly, and the problem of stability is very standout. As the continuous increase of arch’s spanning capability, application of new materials, arch structural integral and partial rigidity comparative declines and makes the problem of arch’s stability even more standout. In this article, through study on stability of arch bridge by finite element method, we discussed arch bridge’s linear and nonlinear finite element solve method.