共查询到20条相似文献,搜索用时 15 毫秒
1.
V. P. Maslov 《Theoretical and Mathematical Physics》2000,125(2):1552-1567
We develop the theory of averaging the operators in a Fock space, introduced in our previous papers. We find the algebra of
mean operators. We introduce the quantum entropy and quantum free energy using the function f(z)=zlog(z) of the mean unit
operator (the “measure” of mean operators). Such a “quantum thermodynamics” determines the temperature dependence of the critical
speed (“the Landau criterion”) and the temperature distribution at which the speed of a superfluid system is nonzero even
at zero temperature. We generalize the consideration to the case where sparsely distributed bosons form clusters.
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 125, No. 2, pp. 297–314, November, 2000. 相似文献
2.
Al. B. Zamolodchikov 《Theoretical and Mathematical Physics》2007,151(1):439-458
We find the four-point perturbative contribution to the spherical partition function of the gravitational Yang-Lee model numerically.
We propose an effective integration procedure based on a convenient elliptic parameterization of the moduli space. At certain
values of the “spectator” parameter, the Liouville four-point function involves several “discrete terms,” which should be
taken into account separately. We also consider the classical limit, where only the discrete terms survive. In addition, we
propose an explicit expression for the spherical partition function at the “second explicitly solvable point,” where the spectator
matter is yet another M
2/5 (Yang-Lee) minimal model.
On leave of absence from the Institute of Theoretical and Experimental Physics, Moscow, Russia; Laboratoire de Physique Mathématique
et Astroparticules, Laboratoire Associé au CNRS UMR 5825, Université Montpellier 2, Montpellier, France; Service de Physique
Théorique CNRS URA 2306, CEA-Saclay, Gif-sur-Yvette, France, e-mail: Aliocha.ZAMOLODCHIKOV@lpta.univ-montp2.fr.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 151, No. 1, pp. 3–25, April, 2007. 相似文献
3.
G. I. Bizhanova 《Journal of Mathematical Sciences》2006,136(2):3672-3681
We construct automodel solutions for the one-dimensional two-phase Stefan, Florin, and Verigin free boundary problems for
parabolic equations in the case where the initial and boundary data are not adjusted. It is shown that in the Stefan problem
with “supercooling,” the liquid temperature may be less than the temperature of the phase transition, i.e., the liquid may
be “supercooled” while the solid may be “superheated.” Bibliography: 8 titles.
Dedicated to the memory of Olga Aleksandrovna Ladyzhenskaya
__________
Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 318, 2004, pp. 42–59. 相似文献
4.
We study the R-controllability (the controllability within the attainability set) and the R-observability of time-varying linear differential-algebraic equations (DAE). We analyze DAE under assumptions guaranteeing
the existence of a structural form (which is called “equivalent”) with separated “differential” and “algebraic” subsystems.
We prove that the existence of this form guarantees the solvability of the corresponding conjugate system, and construct the
corresponding “equivalent form” for the conjugate DAE. We obtain conditions for the R-controllability and R-observability, in particular, in terms of controllability and observability matrices. We prove theorems that establish certain
connections between these properties. 相似文献
5.
Gábor Czédli 《Mathematica Slovaca》2011,61(6):859-870
For each of the relations “less than or equal to”, “less than”, “covered by”, and “covered by or equal to”, we characterize
finite orders (also called posets) with the property that the pair of Galois closure operators induced by the relation in
question coincides with the pair of closure operators introduced and applied in our previous paper in 2007. We also consider
the “less than or equal to” relation between the set of join-irreducible elements and the set of meet-irreducible elements,
and we show that the above-mentioned pairs of closure operators coincide for finite modular lattices. 相似文献
6.
We obtain an expression for the NMR line at low temperatures for a system of nuclear spins described by a Hamiltonian with
equal spin-spin coupling constants. We show that in the case of “easy axis” anisotropy, the line has a logarithmic low-frequency
singularity and an exponentially decreasing high-frequency asymptotic behavior at the temperature of an anomalous peak of
heat capacity. In the case of “easy plane” anisotropy, the line has the traditional Gaussian form. We discuss the possibility
of using NMR data to discover specific thermodynamic and magnetic properties of the considered model system. 相似文献
7.
V. G. Durnev 《Mathematical Notes》2000,67(2):152-159
In the paper we study the algorithmic nature of some “simple” fragments of positive theories with “few” constants for free
noncyclic semigroups.
Translated fromMatematicheskie Zametki, Vol. 67, No. 2, pp. 191–200, February, 2000. 相似文献
8.
We prove a preservation theorem for limit steps of countable support iterations of proper forcing notions whose particular
cases are preservations of the following properties on limit steps: “no random reals are added”, “μ(Random(V))≠1”, “no dominating reals are added”, “Cohen(V) is not comeager”. Consequently, countable support iterations of σ-centered forcing notions do not add random reals.
The work was supported by BRF of Israel Academy of Sciences and by grant GA SAV 365 of Slovak Academy of Sciences. 相似文献
9.
V. A. Berezin 《Theoretical and Mathematical Physics》2012,170(1):71-82
We build a model in which the main global properties of classical and semiclassical black holes become local: these are the
event horizon, “no-hair,” temperature, and entropy. Our construction is based on the features of a quantum collapse, discovered
when studying some particular quantum black hole models. But our model is purely classical, and this allows using the Einstein
equations and classical (local) thermodynamics self-consistently and, in particular, solving the “puzzle of log 3.” 相似文献
10.
We study the properties of the ergosurface of the Pomeransky–Senkov black rings, and show that it splits into an “inner” and
an “outer” region. As for the singular set, the topology of the “outer ergosurface” depends upon the value of parameters. 相似文献
11.
Rade T. Živaljević 《Discrete and Computational Geometry》2009,41(1):135-161
This paper lays the foundation for a theory of combinatorial groupoids that allows us to use concepts like “holonomy”, “parallel transport”, “bundles”, “combinatorial curvature”, etc. in the context
of simplicial (polyhedral) complexes, posets, graphs, polytopes and other combinatorial objects. We introduce a new, holonomy-type
invariant for cubical complexes, leading to a combinatorial “Theorema Egregium” for cubical complexes that are non-embeddable
into cubical lattices. Parallel transport of Hom-complexes and maps is used as a tool to extend Babson–Kozlov–Lovász graph coloring results to more general statements about
nondegenerate maps (colorings) of simplicial complexes and graphs.
The author was supported by grants 144014 and 144026 of the Serbian Ministry of Science and Technology. 相似文献
12.
Alessio Moretti 《Logica Universalis》2009,3(1):19-57
Whereas geometrical oppositions (logical squares and hexagons) have been so far investigated in many fields of modal logic
(both abstract and applied), the oppositional geometrical side of “deontic logic” (the logic of “obligatory”, “forbidden”,
“permitted”, . . .) has rather been neglected. Besides the classical “deontic square” (the deontic counterpart of Aristotle’s
“logical square”), some interesting attempts have nevertheless been made to deepen the geometrical investigation of the deontic
oppositions: Kalinowski (La logique des normes, PUF, Paris, 1972) has proposed a “deontic hexagon” as being the geometrical
representation of standard deontic logic, whereas Joerden (jointly with Hruschka, in Archiv für Rechtsund Sozialphilosophie
73:1, 1987), McNamara (Mind 105:419, 1996) and Wessels (Die gute Samariterin. Zur Struktur der Supererogation, Walter de Gruyter,
Berlin, 2002) have proposed some new “deontic polygons” for dealing with conservative extensions of standard deontic logic
internalising the concept of “supererogation”. Since 2004 a new formal science of the geometrical oppositions inside logic
has appeared, that is “n-opposition theory”, or “NOT”, which relies on the notion of “logical bi-simplex of dimension m” (m = n − 1). This theory has received a complete mathematical foundation in 2008, and since then several extensions. In this paper,
by using it, we show that in standard deontic logic there are in fact many more oppositional deontic figures than Kalinowski’s
unique “hexagon of norms” (more ones, and more complex ones, geometrically speaking: “deontic squares”, “deontic hexagons”,
“deontic cubes”, . . ., “deontic tetraicosahedra”, . . .): the real geometry of the oppositions between deontic modalities
is composed by the aforementioned structures (squares, hexagons, cubes, . . ., tetraicosahedra and hyper-tetraicosahedra),
whose complete mathematical closure happens in fact to be a “deontic 5-dimensional hyper-tetraicosahedron” (an oppositional
very regular solid).
相似文献
13.
We study Lebesgue and Atsuji spaces within subsystems of second order arithmetic. The former spaces are those such that every
open covering has a Lebesgue number, while the latter are those such that every continuous function defined on them is uniformly
continuous. The main results we obtain are the following: the statement “every compact space is Lebesgue” is equivalent to
; the statements “every perfect Lebesgue space is compact” and “every perfect Atsuji space is compact” are equivalent to ; the statement “every Lebesgue space is Atsuji” is provable in ; the statement “every Atsuji space is Lebesgue” is provable in . We also prove that the statement “the distance from a closed set is a continuous function” is equivalent to .
Received: February 2, 1996 相似文献
14.
Xingwei Hu 《International Journal of Game Theory》2006,34(2):229-240
This paper extends the traditional “pivoting” and “swing” schemes in the Shapley–Shubik (S-S) power index and the Banzhaf index to the case of “blocking”. Voters are divided into two groups: those who vote for the bill and those against the bill. The uncertainty of the division is described by a probability distribution. We derive the S-S power index, based on a priori ignorance about the random bipartition. 相似文献
15.
A. T. Filippov 《Theoretical and Mathematical Physics》2010,163(3):753-767
We propose new models of the “affine” theory of gravity in multidimensional space-times with symmetric connections. We use
and develop ideas of Weyl, Eddington, and Einstein, in particular, Einstein’s proposed method for obtaining the geometry using
the Hamilton principle. More specifically, the connection coefficients are determined using a “geometric” Lagrangian that
is an arbitrary function of the generalized (nonsymmetric) Ricci curvature tensor (and, possibly, other fundamental tensors)
expressed in terms of the connection coefficients regarded as independent variables. Such a theory supplements the standard
Einstein theory with dark energy (the cosmological constant, in the first approximation), a neutral massive (or tachyonic)
meson, and massive (or tachyonic) scalar fields. These fields couple only to gravity and can generate dark matter and/or inflation.
The new field masses (real or imaginary) have a geometric origin and must appear in any concrete model. The concrete choice
of the Lagrangian determines further details of the theory, for example, the nature of the fields that can describe massive
particles, tachyons, or even “phantoms.” In “natural” geometric theories, dark energy must also arise. The basic parameters
of the theory (cosmological constant, mass, possible dimensionless constants) are theoretically indeterminate, but in the
framework of modern “multiverse” ideas, this is more a virtue than a defect. We consider further extensions of the affine
models and in more detail discuss approximate effective (“physical”) Lagrangians that can be applied to the cosmology of the
early Universe. 相似文献
16.
We introduce in this paper the concept of “impulse evolutionary game”. Examples of evolutionary games are usual differential
games, differentiable games with history (path-dependent differential games), mutational differential games, etc. Impulse
evolutionary systems and games cover in particular “hybrid systems” as well as “qualitative systems”. The conditional viability
kernel of a constrained set (with a target) is the set of initial states such that for all strategies (regarded as continuous
feedbacks) played by the second player, there exists a strategy of the first player such that the associated run starting
from this initial state satisfies the constraints until it hits the target. This paper characterizes the concept of conditional
viability kernel for “qualitative games” and of conditional valuation function for “qualitative games” maximinimizing an intertemporal
criterion. The theorems obtained so far about viability/capturability issues for evolutionary systems, conditional viability
for differential games and about impulse and hybrid systems are used to provide characterizations of conditional viability
under impulse evolutionary games. 相似文献
17.
Sylvia Chiang 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2006,151(1):940-959
We study the pressureless gas equations, with piecewise constant initial data. In the immediate solution, δ-shocks and contact
vacuum states arise and even meet (interact) eventually. A solution beyond the “interaction” is constructed. It shows that
the δ-shock will continue with the velocity it attained instantaneously before the time of interaction, and similarly, the
contact vacuum state will move past the δ-shock with a velocity value prior to the interaction. We call this the “no-effect-from-interaction”
solution.
We prove that this solution satisfies a family of convex entropies (in the Lax’s sense). Next, we construct an infinitely
large family of weak solutions to the “interaction”. Suppose further that any of these solutions satisfy a convex entropy,
it is necessary and suffcient that these solutions reduce to only the “no-effect-from-interaction” solution. In [1], Bouchut
constructed another entropy satisfying solution. As with other previous papers, it is obvious that it will not be sufficient
that a “correct” solution satisfies a convex entropy, in a non-strictly hyperbolic conservation laws system. 相似文献
18.
We show the equivalence of categories of model-theoretic imaginaries (of various kinds) with categories of “small” (finitely
generated, finitely presented, coherent) functors. We do this first for certain locally finitely presented categories and
then, by localising, for much more general “definable categories” (categories of models of coherent theories). We also investigate
the corresponding notion of interpretation. 相似文献
19.
There are two types of random phenomena modeled in stochastic programs. One type is what we may term “external” or “natural”
random variables, such as temperature or the roll of a dice. But in many other cases, random variables are used to reflect
the behavior of other market participants. This is the case for such as price and demand of a product. Using simple game theoretic
models, we demonstrate that stochastic programming may not be appropriate in these cases, as there may be no feasible way
to replace the decisions of others by a random variable, and arrive at the correct decision. Hence, this simple note is a
warning against certain types of stochastic programming models. Stochastic programming is unproblematic in pure forms of monopoly
and perfect competition, and also with respect to external random phenomena. But if market power is involved, such as in oligopolies,
the modeling may not be appropriate. 相似文献
20.
We are interested in the maximum possible number of facets that Dirichlet stereohedra for three-dimensional crystallographic
groups can have. In two previous papers, D. Bochiş and the second author studied the problem for noncubic groups. This paper
deals with “full” cubic groups, while “quarter” cubic groups are left for a subsequent paper. Here, “full” and “quarter” refers
to the recent classification of three-dimensional crystallographic groups by Conway, Delgado-Friedrichs, Huson and Thurston.
This paper’s main result is that Dirichlet stereohedra for any of the 27 full groups cannot have more than 25 facets. We also
find stereohedra with 17 facets for one of these groups.
Research partially supported by the Spanish Ministry of Education and Science, grant number MTM2005-08618-C02-02. 相似文献