Revising and updating beliefs and knowledge bases is an important topic in knowledge representation and reasoning that requires a solid theoretical basis. As a result, various researchers have proposed Answer Set Programming as one of their key components to set up their approaches. In the need to satisfy more general principles, this paper presents a new characterisation of a semantics. It con...

Theoretical ab initio calculations are reported of the cross sections for dissociative recombination of the lowest four excited vibrational levels of N2(+) at electron energies from 0.001 to 1.0 eV. Rydberg vibrational levels contributing to the cross section structures are identified as are dissociative channels contributing more than 10(-16) cm(2) to the total cross sections. In contrast to t...

We show that if the fundamental group π of an inde-composable orientable P D 3-complex is the fundamental group of a finite graph of finite groups then the vertex groups have periodic cohomology and the edge groups are metacyclic. If the vertex groups all have cohomological period dividing 4 at most one is not dihedral, the edge groups are Z/2Z, and the underlying graph is a tree. We also ask w...

We characterize groups with Guoliang Yu’s property A (i.e., exact groups) by the existence of a family of uniformly bounded representations which approximate the trivial representation. Property A is a large scale geometric property that can be viewed as a weak counterpart of amenability. It was shown in [12], that for a finitely generated group property A implies the Novikov conjecture. It was...

We study multiplicative Dirac structures on Lie groups. We show that the characteristic foliation of a multiplicative Dirac structure is given by the cosets of a normal Lie subgroup and, whenever this subgroup is closed, the leaf space inherits the structure of a Poisson-Lie group. We also describe multiplicative Dirac structures on Lie groups infinitesimally. Résumé Nous étudions les structure...

We investigate large-scale galactic winds driven by momentum deposition. Momentum injection is provided by (1) radiation pressure produced by the continuum absorption and scattering of photons on dust grains and (2) supernovae (momentum injection by supernovae is important even if the supernovae energy is radiated away). Radiation can be produced by a starburst or AGN activity. We argue that mo...

Based on the Ward-Takahashi identity for the BRS symmetry, we prove to all orders of the loop expansion the low energy theorem of hidden local symmetry for the vector mesons (KSRF (I) relation) in the U(N)L × U(N)R / U(N)V nonlinear chiral Lagrangian. ∗Address after April 1, 1993 : Department of Physics, Kyoto University, Kyoto 606-01, Japan Hidden local symmetry (HLS) is a natural framework fo...

and Applied Analysis 3 or the modified Mann iterative sequence method xn 1 QG ( 1 − αn xn αnT ΠGT xn ) , n 1, 2, . . . , x1 ∈ G, 1.6 where QG : B → G is a sunny nonexpansive retraction. So, in some ways, our results extend and improve some results of other authors such as, see 1–5, 7, 9–13 , from self mappings to non-self-mappings, from Hilbert spaces to Banach spaces. 2. Preliminaries In the s...

H2 is the most abundant molecule in the universe and is an active component of star formation. Inside dense molecular clouds, heating and ionization occur by cosmic rays, X-rays and shock waves, generating energetic electrons. Collisional excitation by electrons is the source of both UV and Visible-optical-IR (VOIR) H2 fluorescence in the ISM, circumstellar disks and certain classes of stars [1...

Tentative observations and theoretical considerations have recently led to renewed interest in models of fundamental physics in which certain “constants” vary in time. Davies, Davis and Lineweaver [1] have argued that the laws of black hole thermodynamics disfavor models in which the fundamental electric charge e changes. I show that similar considerations severely constrain “varying speed of l...