Search results for "finite [mass]"
showing 10 items of 356 documents
On finite T-groups
2003
[EN] Characterisations of finite groups in which normality is a transitive relation are presented in the paper. We also characterise the finite groups in which every subgroup is either permutable or coincides with its permutiser as the groups in which every subgroup is permutable.
Tunnel effect and symmetries for Kramers–Fokker–Planck type operators
2011
AbstractWe study operators of Kramers–Fokker–Planck type in the semiclassical limit, assuming that the exponent of the associated Maxwellian is a Morse function with a finite number n0 of local minima. Under suitable additional assumptions, we show that the first n0 eigenvalues are real and exponentially small, and establish the complete semiclassical asymptotics for these eigenvalues.
Lower bounds for eigenvalues of a quadratic form relative to a positive quadratic form
1968
Abstract : A method is presented for the calculation of lower bounds to eigenvalues of operators that arise from variational problems for one quadratic form relative to a positive definite quadratic form. Eigenvalue problems of this kind occur, for example, in the theory of buckling of continuous linear elastic systems. The technique used is a modification of one introduced earlier, (1) sections II and IVB, for the determination of lower bounds to eigenvalues of semi-bounded self-adjoint operators. Other methods for the latter problem can be carried over without essential changes. The particular difficulty in the case we consider is that some operators which enter the calculation for the lo…
Fokker Planck equation solved in terms of complex fractional moments
2014
Abstract In this paper the solution of the Fokker Planck (FPK) equation in terms of (complex) fractional moments is presented. It is shown that by using concepts coming from fractional calculus, complex Mellin transform and related ones, the solution of the FPK equation in terms of a finite number of complex moments may be easily found. It is shown that the probability density function (PDF) solution of the FPK equation is restored in the whole domain, including the trend at infinity with the exception of the value of the PDF in zero.
Two-variable logics with counting and semantic constraints
2018
In this article we discuss fragments and extensions of two-variable logics motivated by practical applications. We outline the decidability frontier, describing some of the techniques developed for deciding satisfiability and finite satisfiability, as well as characterizing their complexity.
Verification of Well-Formed Communicating Recursive State Machines
2008
AbstractIn this paper we introduce a new (non-Turing equivalent) formal model of recursive concurrent programs called well-formed communicating recursive state machines (CRSM). CRSM extend recursive state machines (RSM) by allowing a restricted form of concurrency: a state of a module can be refined into a finite collection of modules (working in parallel) in a potentially recursive manner. Communication is only possible between the activations of modules invoked on the same fork. We study the model-checking problem of CRSM with respect to specifications expressed in a temporal logic that extends CaRet with a parallel operator (ConCaRet). We propose a decision algorithm that runs in time ex…
Character correspondences in blocks with normal defect groups
2014
Abstract In this paper we give an extension of the Glauberman correspondence to certain characters of blocks with normal defect groups.
A Positive Definite Advection Scheme for Use in Long Range Transport Models: Extension to Monotonicity
1992
Numerical modeling of atmospheric transport processes requires the solution of the continuity equation for prognostic variables such as momentum, heat, water vapor, liquid water or chemical species of the atmosphere. Although in the literature many advection schemes are known to solve this problem (Lax and Wendroff 1964, Crowley 1968, Tremback et al. 1987, Bott 1989a,b), these algorithms show different disadvantages, which sometimes yield undesirably poor numerical results. For instance, the upstream method is known to produce large numerical diffusion. The higher order versions of the advection schemes of Tremback et al. (1987) are much less diffusive. Unfortunately, the schemes are not po…
CODING PARTITIONS OF REGULAR SETS
2009
A coding partition of a set of words partitions this set into classes such that whenever a sequence, of minimal length, has two distinct factorizations, the words of these factorizations belong to the same class. The canonical coding partition is the finest coding partition that partitions the set of words in at most one unambiguous class and other classes that localize the ambiguities in the factorizations of finite sequences. We prove that the canonical coding partition of a regular set contains a finite number of regular classes and we give an algorithm for computing this partition. From this we derive a canonical decomposition of a regular monoid into a free product of finitely many re…
Quantum Finite One-Counter Automata
1999
In this paper the notion of quantum finite one-counter automata (QF1CA) is introduced. Introduction of the notion is similar to that of the 2-way quantum finite state automata in [1]. The well-formedness conditions for the automata are specified ensuring unitarity of evolution. A special kind of QF1CA, called simple, that satisfies the well-formedness conditions is introduced. That allows specify rules for constructing such automata more naturally and simpler than in general case. Possible models of language recognition by QF1CA are considered. The recognition of some languages by QF1CA is shown and compared with recognition by probabilistic counterparts.