A ring $R$ with an automorphism $sigma$ and a $sigma$-derivation $delta$ is called $delta$-quasi-Baer (resp., $sigma$-invariant quasi-Baer) if the right annihilator of every $delta$-ideal (resp., $sigma$-invariant ideal) of $R$ is generated by an idempotent, as a right ideal. In this paper, we study Baer and quasi-Baer properties of skew PBW extensions. More exactly, let $A=sigma(R)leftlangle x...

We prove the existance and uniqueness of quasi-invariant measure on double cost space K\G/H and study the Fourier and Fourier-Stieltjes algebras of these spaces

A subshift on a group G is a closed, G-invariant subset of A, for some finite set A. It is said to be of finite type if it is defined by a finite collection of “forbidden patterns” and to be strongly aperiodic if it has no points fixed by a nontrivial element of the group. We show that if G has at least two ends, then there are no strongly aperiodic subshifts of finite type on G (as was previou...

Height restricted resolution (proofs or refutations) is a natural restriction of resolution where the height of the corresponding proof tree is bounded. Height restricted resolution does not distinguish between treeand sequence-like proofs. We show that polylogarithmic-height resolution is strongly connected to the bounded arithmetic theory S 2(α). We separate polylogarithmic-height resolution ...