On $ p $ -Universal and $ p $ -Minimal Numberings

Siberian Mathematical Journal - We study the $ p $ -reducibility of numberings which was introduced and first studied by Degtev. $ p $ -Reducibility is an effectively bounded version of the $ e $...     

Nonlinear Mixed Jordan Triple $ * $ -Derivations on $ * $ -Algebras

Siberian Mathematical Journal - Let $ {\mathcal{A}} $ be a unital $ \ast $ -algebra containing a nontrivial projection. Under some mild conditions on  $ {\mathcal{A}} $ ,...     

$ P $ -Stability of Some Classes of $ S $ -Acts

Siberian Mathematical Journal - The notion of $ P $ -stability is a particular case of the generalized stability of complete theories. This paper discusses some problems that are related to the $ P...     

Almost $ \omega $ -Categorical Weakly $ o $ -Minimal Theories of Convexity Rank 1

Siberian Mathematical Journal - Studying the properties of almost $ \omega $ -categorical weakly $ o $ -minimal theories of convexity rank 1, we prove the orthogonality of every family of...     

A Criterion for Binarity of Almost $ \omega $ -Categorical Weakly $ o $ -Minimal Theories

Siberian Mathematical Journal - Continuing the study of weak $ o $ -minimality, we prove a theorem on the behavior of a definable unary function on the set of realizations of a nonalgebraic 1-type...     

Generalized Rickart $ \ast $ -Rings

Siberian Mathematical Journal - As a common generalization of Rickart $ \ast $ -rings and generalized Baer $ \ast $ -rings, we say that a ring  $ R $ with an involution ...     

Yamabe Invariants and $ Spin^c $ Structures

The Yamabe invariant of a smooth compact manifold is by definition the supremum of the scalar curvatures of unit-volume Yamabe metrics on the manifold. For an explicit infinite class of 4-manifolds, we show that this invariant is positive but strictly less than that of the 4-sphere. This is done by using Dirac operators to control the lowest eigenvalue of a perturbation of the Yamabe Laplacian. These results dovetail perfectly with those derived from the perturbed Seiberg–Witten equations [Le3], but the present method is much more elementary in spirit. Submitted: October 1997     

A New Characterization of Finite $ \sigma $ -Soluble $ P\sigma T $ -Groups

Siberian Mathematical Journal - We prove that  $ G $ is a finite $ \sigma $ -soluble group with transitive $ \sigma $ -permutability if and only if the following hold: (i) $ G $ possesses...     

Frobenius $ \mathbb Q $ -groups

A finite group whose irreducible complex characters are rational is called a -group. In this paper we will find the structure of Frobenius -groups.Received: 14 April 2003