scholarly journals GENERIC STABILITY AND STABILITY

2014 ◽  
Vol 79 (01) ◽  
pp. 179-185 ◽  
Author(s):  
HANS ADLER ◽  
ENRIQUE CASANOVAS ◽  
ANAND PILLAY
Keyword(s):  
Full Generality ◽  
Generic Stability ◽  
Special Cases

AbstractWe prove two results about generically stable typespin arbitrary theories. The first, on existence of strong germs, generalizes results from [2] on stably dominated types. The second is an equivalence of forking and dividing, assuming generic stability ofp(m)for allm. We use the latter result to answer in full generality a question posed by Hasson and Onshuus: IfP(x) εS(B) is stable and does not fork overAthenprestrictionAis stable. (They had solved some special cases.)

scholarly journals Theoretical framework for higher-order quantum theory

2019 ◽  
Vol 475 (2225) ◽  
pp. 20180706 ◽  
Author(s):  
Alessandro Bisio ◽  
Paolo Perinotti
Keyword(s):  
Quantum Theory ◽  
Convex Sets ◽  
Mathematical Structure ◽  
Higher Order ◽  
Equivalence Relations ◽  
Full Generality ◽  
Special Cases ◽  
Different Types ◽  
Causal Structures

Higher-order quantum theory is an extension of quantum theory where one introduces transformations whose input and output are transformations, thus generalizing the notion of channels and quantum operations. The generalization then goes recursively, with the construction of a full hierarchy of maps of increasingly higher order. The analysis of special cases already showed that higher-order quantum functions exhibit features that cannot be tracked down to the usual circuits, such as indefinite causal structures, providing provable advantages over circuital maps. The present treatment provides a general framework where this kind of analysis can be carried out in full generality. The hierarchy of higher-order quantum maps is introduced axiomatically with a formulation based on the language of types of transformations. Complete positivity of higher-order maps is derived from the general admissibility conditions instead of being postulated as in previous approaches. The recursive characterization of convex sets of maps of a given type is used to prove equivalence relations between different types. The axioms of the framework do not refer to the specific mathematical structure of quantum theory, and can therefore be exported in the context of any operational probabilistic theory.

scholarly journals Sur l'homologie des groupes unitaires à coefficients polynomiaux

2012 ◽  
Vol 10 (1) ◽  
pp. 87-139 ◽  
Author(s):  
Aurélien Djament
Keyword(s):  
Unitary Groups ◽  
Symmetric Power ◽  
Orthogonal Groups ◽  
Tensor Power ◽  
Full Generality ◽  
Standard Methods ◽  
Homology Groups ◽  
Special Cases ◽  
Functor Homology ◽  
Kunneth Formula

AbstractLet A be a ring with anti-involution and F a nice functor (tensor or symmetric power, for example) from finitely-generated projective A-modules to abelian groups. We show that the homology of the hyperbolic unitary groups Un,n(A) with coefficients in F(A2n) can be expressed stably (i.e. after taking the colimit over n) by the homology of these groups with untwisted coefficients and functor homology groups that we can compute in suitable cases (for example, when A is a field of characteristic 0 or a ring without ℤ-torsion and F a tensor power). This extends the result where A is a finite field, which was dealt with previously by C. Vespa and the author (Ann. Sci. ENS, 2010).The proof begins by relating, without any assumption on F, our homology groups to the homology of a category of hermitian spaces with coefficients twisted by F. Then, when F is polynomial, we establish — following a method due to Scorichenko — an isomorphism between this homology and the homology of another category of (possibly degenerate) hermitian spaces, which is computable (in good cases) by standard methods of homological algebra in functor categories (using adjunctions, Künneth formula…). We give some examples.Finally, we deal with the analogous problem for non-hyperbolic unitary groups in some special cases, for example euclidean orthogonal groups On (A) (the ring A being here commutative). The isomorphism between functor homology and group homology with twisted coefficients does not hold in full generality; nevertheless we succeed to get it when A is a field or, for example, a subring of ℚ containing ℤ[1/2]. The method, which is similar to that in the previous case, uses a general result of symmetrisation in functor homology proved at the beginning of the article.

scholarly journals A boundary value problem on an infinite interval

1975 ◽  
Vol 19 (3) ◽  
pp. 245-252 ◽  
Author(s):  
Athanassios G. Kartsatos
Keyword(s):  
Boundary Value Problem ◽  
Fixed Point Theorems ◽  
Boundary Value ◽  
Series Representation ◽  
Full Generality ◽  
Bounded Linear ◽  
Special Cases ◽  
Infinite Intervals ◽  
Image Position ◽  
Scalar Equations

We are interested here in proving the existence of solutions to the (generalised) boundary value problemwhere A is a continuous n×n matrix on R+ = [0, ∞), F is a continuous n vector on R+ × S (S = a suitable subset of Rn), T is a bounded linear operator defined on (or on a subspace of) C[R+, Rn], the space of all bounded and continuous Rn-valued functions on R+, and r is a fixed vector in Rn. There is an abundance of papers dealing with the problem ((I), (II)) on finite intervals, either in its full generality (cf., for example, (1), (2), (3), (4), (6)), or for special cases of the operator T. The reader is especially referred to the work of Shreve (7), (8) for such problems on infinite intervals for scalar equations. A series representation of the solutions is given by Kravchenko and Yablonskii (5). Most of our methods are extensions of the corresponding ones on finite intervals with some variations concerning the application of fixed-point theorems. Examples of interesting operators T arewhere V(t), M, N are n×n matrices with V(t) integrable.

scholarly journals ON CUBATURE RULES ASSOCIATED TO WEYL GROUP ORBIT FUNCTIONS

2016 ◽  
Vol 56 (3) ◽  
pp. 202 ◽  
Author(s):  
Lenka Háková ◽  
Jiří Hrivnák ◽  
Lenka Motlochová
Keyword(s):  
Weyl Group ◽  
Lie Algebra ◽  
Lie Algebras ◽  
Jacobi Polynomials ◽  
Special Functions ◽  
Root Systems ◽  
Full Generality ◽  
Cubature Formulas ◽  
Special Cases ◽  
Group Orbit

The aim of this article is to describe several cubature formulas related to the Weyl group orbit functions, i.e. to the special cases of the Jacobi polynomials associated to root systems. The diagram containing the relations among the special functions associated to the Weyl group orbit functions is presented and the link between the Weyl group orbit functions and the Jacobi polynomials is explicitly derived in full generality. The four cubature rules corresponding to these polynomials are summarized for all simple Lie algebras and their properties simultaneously tested on model functions. The Clenshaw-Curtis method is used to obtain additional formulas connected with the simple Lie algebra <em>C</em><sub>2</sub>.

Doppler Broadened Spectral Functions and Time Correlation Functions for a Gas in Non-Equilibrium

1977 ◽  
Vol 32 (11) ◽  
pp. 1239-1244
Author(s):  
S. Hess ◽  
A. Mörtel
Keyword(s):  
Equilibrium Distribution ◽  
Velocity Distribution Function ◽  
Time Correlation ◽  
Time Correlation Function ◽  
Spectral Functions ◽  
Equilibrium Conditions ◽  
Full Generality ◽  
Equilibrium Processes ◽  
Special Cases ◽  
Non Equilibrium

AbstractUnder non-equilibrium conditions, the velocity distribution function of a gas differs from the Maxwellian equilibrium distribution. The effect of this deviation from equilibrium on the time correlation function and the spectral function associated with a Doppler broadened spectral line is calculated in full generality for stationary non-equilibrium processes. As special cases the heat conduction and the viscous flow in the hydrodynamic regime are discussed.

scholarly journals Strong Stubborn Set Pruning for Star-Topology Decoupled State Space Search

2019 ◽  
Vol 65 ◽  
pp. 343-392
Author(s):  
Daniel Gnad ◽  
Jörg Hoffmann ◽  
Martin Wehrle
Keyword(s):  
State Space ◽  
Complex Structure ◽  
Optimal Solution ◽  
Search Space ◽  
Ai Planning ◽  
Full Generality ◽  
Star Topology ◽  
State Space Search ◽  
Special Cases ◽  
Fixed Path

Analyzing reachability in large discrete transition systems is an important sub-problem in several areas of AI, and of CS in general. State space search is a basic method for conducting such an analysis. A wealth of techniques have been proposed to reduce the search space without affecting the existence of (optimal) solution paths. In particular, strong stubborn set (SSS) pruning is a prominent such method, analyzing action dependencies to prune commutative parts of the search space. We herein show how to apply this idea to star-topology decoupled state space search, a recent search reformulation method invented in the context of classical AI planning. Star-topology decoupled state space search, short decoupled search, addresses planning tasks where a single center component interacts with several leaf components. The search exploits a form of conditional independence arising in this setting: given a fixed path p of transitions by the center, the possible leaf moves compliant with p are independent across the leaves. Decoupled search thus searches over center paths only, maintaining the compliant paths for each leaf separately. This avoids the enumeration of combined states across leaves. Just like standard search, decoupled search is adversely affected by commutative parts of its search space. The adaptation of strong stubborn set pruning is challenging due to the more complex structure of the search space, and the resulting ways in which action dependencies may affect the search. We spell out how to address this challenge, designing optimality-preserving decoupled strong stubborn set (DSSS) pruning methods. We introduce a design for star topologies in full generality, as well as simpler design variants for the practically relevant fork and inverted fork special cases. We show that there are cases where DSSS pruning is exponentially more effective than both, decoupled search and SSS pruning, exhibiting true synergy where the whole is more than the sum of its parts. Empirically, DSSS pruning reliably inherits the best of its components, and sometimes outperforms both.

Electron Beam Damage of Biomolecules Assessed by Energy Loss Spectroscopy

1978 ◽  
Vol 36 (3) ◽  
pp. 61-69
Author(s):  
M. Isaacson ◽  
M.L. Collins ◽  
M. Listvan
Keyword(s):  
Electron Microscopy ◽  
Radiation Damage ◽  
Structural Integrity ◽  
Analytical Electron Microscopy ◽  
High Dose ◽  
Dose Rates ◽  
Special Cases ◽  
Analytical Electron ◽  
Atom Migration ◽  
Beam Damage

Over the past five years it has become evident that radiation damage provides the fundamental limit to the study of blomolecular structure by electron microscopy. In some special cases structural determinations at very low doses can be achieved through superposition techniques to study periodic (Unwin & Henderson, 1975) and nonperiodic (Saxton & Frank, 1977) specimens. In addition, protection methods such as glucose embedding (Unwin & Henderson, 1975) and maintenance of specimen hydration at low temperatures (Taylor & Glaeser, 1976) have also shown promise. Despite these successes, the basic nature of radiation damage in the electron microscope is far from clear. In general we cannot predict exactly how different structures will behave during electron Irradiation at high dose rates. Moreover, with the rapid rise of analytical electron microscopy over the last few years, nvicroscopists are becoming concerned with questions of compositional as well as structural integrity. It is important to measure changes in elemental composition arising from atom migration in or loss from the specimen as a result of electron bombardment.

Decoration technique and surface physics

1978 ◽  
Vol 36 (1) ◽  
pp. 436-437 ◽  
Author(s):  
H. Bethge
Keyword(s):  
Diffusion Path ◽  
Special Importance ◽  
Surface Physics ◽  
Step Structure ◽  
Initial Stage ◽  
Special Cases ◽  
Atomic Surface ◽  
The Mean ◽  
Bulk Structure ◽  
Decoration Technique

Besides the atomic surface structure, diverging in special cases with respect to the bulk structure, the real structure of a surface Is determined by the step structure. Using the decoration technique /1/ it is possible to image step structures having step heights down to a single lattice plane distance electron-microscopically. For a number of problems the knowledge of the monatomic step structures is important, because numerous problems of surface physics are directly connected with processes taking place at these steps, e.g. crystal growth or evaporation, sorption and nucleatlon as initial stage of overgrowth of thin films.To demonstrate the decoration technique by means of evaporation of heavy metals Fig. 1 from our former investigations shows the monatomic step structure of an evaporated NaCI crystal. of special Importance Is the detection of the movement of steps during the growth or evaporation of a crystal. From the velocity of a step fundamental quantities for the molecular processes can be determined, e.g. the mean free diffusion path of molecules.

One Size Fits All?

Methodology ◽  
2012 ◽  
Vol 8 (1) ◽  
pp. 23-38 ◽  
Author(s):  
Manuel C. Voelkle ◽  
Patrick E. McKnight
Keyword(s):  
Repeated Measures ◽  
Structural Equation ◽  
Type I Error ◽  
Equation Modeling ◽  
Type I ◽  
Finite Sample ◽  
Traditional Methods ◽  
Repeated Measures Anova ◽  
Special Cases ◽  
Latent Curve

The use of latent curve models (LCMs) has increased almost exponentially during the last decade. Oftentimes, researchers regard LCM as a “new” method to analyze change with little attention paid to the fact that the technique was originally introduced as an “alternative to standard repeated measures ANOVA and first-order auto-regressive methods” (Meredith & Tisak, 1990, p. 107). In the first part of the paper, this close relationship is reviewed, and it is demonstrated how “traditional” methods, such as the repeated measures ANOVA, and MANOVA, can be formulated as LCMs. Given that latent curve modeling is essentially a large-sample technique, compared to “traditional” finite-sample approaches, the second part of the paper addresses the question to what degree the more flexible LCMs can actually replace some of the older tests by means of a Monte-Carlo simulation. In addition, a structural equation modeling alternative to Mauchly’s (1940) test of sphericity is explored. Although “traditional” methods may be expressed as special cases of more general LCMs, we found the equivalence holds only asymptotically. For practical purposes, however, no approach always outperformed the other alternatives in terms of power and type I error, so the best method to be used depends on the situation. We provide detailed recommendations of when to use which method.

Penile Fracture-Report of Two Cases and Review of Current Literature

KYAMC Journal ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 122-125
Author(s):  
Ashraf Uddin Mallik ◽  
Mostafizur Rahman ◽  
Fatema Bagum ◽  
Uttam Karmaker ◽  
Baikali Ferdous ◽  
...  
Keyword(s):  
Tunica Albuginea ◽  
Traumatic Rupture ◽  
Penile Fracture ◽  
Corpora Cavernosa ◽  
Effective Treatment Modality ◽  
Special Cases ◽  
History Of ◽  
Penile Injury ◽  
Urological Emergency ◽  
Erect Penis

Penile fracture is an uncommon urological emergency, especially in Bangladesh. The other name is traumatic rupture of the tunica albuginea and corpora cavernosa in the erect penis. It occurs when an erect penis face to buckle under the pressure of a blunt sexual trauma. Patient gives the typical history of immediate detumescence, severe pain, swelling and eggplant deformity of the penile shaft due to penile injury. Immediate surgical exploration and repair of corpora Cavernosa with tunica albugenia is the most effective treatment modality. In normal cases diagnosis is made from history, physical examination alone. In some special cases ultrasonogram, radiological images, including retrograde urethrography or cavernosography are mandatory for proper diagnosis. KYAMC Journal Vol. 10, No.-2, July 2019, Page 122-125

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