Partitions and their lattices

Ferrers graphs and tables of partitions are treated as vectors. Matrix operations are used for simple proofs of identities concerning partitions. Interpreting partitions as vectors gives a possibility to generalize partitions on negative numbers. Partitions are then tabulated into lattices and some properties of these lattices are studied. There appears a new identity counting Ferrers graphs packed consecutively into isoscele form. The lattices form the base for tabulating combinatorial identities

First-order transition in XYXY model with higher-order interactions

The effect of inclusion of higher-order interactions in the {\it XY} model on critical properties is studied by Monte Carlo simulations. It is found that an increasing number of the higher-order terms in the Hamiltonian modifies the shape of the potential, which beyond a certain value leads to the change of the nature of the transition from continuous to first order. The evidence for the first-order transition is provided in the form of the finite-size scaling and the energy histogram analysis. A rough phase diagram is presented as a function of the number of the higher-order interaction terms.Comment: 6 pages, 5 figures, 6th International Conference on Mathematical Modeling in Physical Science

On Stability of Non-inflectional Elastica

This study considers the stability of a non-inflectional elastica under a conservative end force subject to the Dirichlet, mixed, and Neumann boundary conditions. It is demonstrated that the non-inflectional elastica subject to the Dirichlet boundary conditions is unconditionally stable, while for the other two boundary conditions, sufficient criteria for stability depend on the signs of the second derivatives of the tangent angle at the endpoints

On the Efficient Gerschgorin Inclusion Usage in the Global Optimization {\alpha}BB Method

In this paper, we revisit the {\alpha}BB method for solving global optimization problems. We investigate optimality of the scaling vector used in Gerschgorin's inclusion theorem to calculate bounds on the eigenvalues of the Hessian matrix. We propose two heuristics to compute good scaling vector d, and state three necessary optimality conditions for optimal d. Since the scaling vector calculated by the second presented method satisfies all three optimality conditions, it serves as a cheap but efficient solution

ThermalSim: A Thermal Simulator for Error Analysis

Researchers have extensively explored predictive control strategies for controlling heating, ventilation, and air conditioning (HVAC) units in commercial buildings. Predictive control strategies, however, critically rely on weather and occupancy forecasts. Existing state-of-the-art building simulators are incapable of analysing the influence of prediction errors (in weather and occupancy) on HVAC energy consumption and occupant comfort. In this paper, we introduce ThermalSim, a building simulator that can quantify the effect of prediction errors on the HVAC operations. ThermalSim has been implemented in C/C++ and MATLAB. We describe its design, use, and input format

Eigenvalues of symmetric tridiagonal interval matrices revisited

In this short note, we present a novel method for computing exact lower and upper bounds of eigenvalues of a symmetric tridiagonal interval matrix. Compared to the known methods, our approach is fast, simple to present and to implement, and avoids any assumptions. Our construction explicitly yields those matrices for which particular lower and upper bounds are attained

There is Neither Classical Bug with a Superluminal Shadow Nor Quantum Absolute Collapse Nor (Subquantum) Superluminal Hidden Variable

In this work we analyse critically Griffiths's example of the classical superluminal motion of a bug shadow. Griffiths considers that this example is conceptually very close to quantum nonlocality or superluminality,i.e. quantum breaking of the famous Bell inequality. Or, generally, he suggests implicitly an absolute asymmetric duality (subluminality vs. superluminality) principle in any fundamental physical theory.It, he hopes, can be used for a natural interpretation of the quantum mechanics too. But we explain that such Griffiths's interpretation retires implicitly but significantly from usual, Copenhagen interpretation of the standard quantum mechanical formalism. Within Copenhagen interpretation basic complementarity principle represents, in fact, a dynamical symmetry principle (including its spontaneous breaking, i.e. effective hiding by measurement). Similarly, in other fundamental physical theories instead of Griffiths's absolute asymmetric duality principle there is a dynamical symmetry (including its spontaneous breaking, i.e. effective hiding in some of these theories) principle. Finally, we show that Griffiths's example of the bug shadow superluminal motion is definitely incorrect (it sharply contradicts the remarkable Roemer's determination of the speed of light by coming late of Jupiter's first moon shadow).Comment: 15 pages, no figure

Statistical test of Duane-Hunt's law and its comparison with an alternative law

Using Pearson correlation coefficient a statistical analysis of Duane-Hunt and Kulenkampff's measurement results was performed. This analysis reveals that empirically based Duane-Hunt's law is not entirely consistent with the measurement data. The author has theoretically found the action of electromagnetic oscillators, which corresponds to Planck's constant, and also has found an alternative law based on the classical theory. Using the same statistical method, this alternative law is likewise tested, and it is proved that the alternative law is completely in accordance with the measurements. The alternative law gives a relativistic expression for the energy of electromagnetic wave emitted or absorbed by atoms and proves that the empirically derived Planck-Einstein's expression is only valid for relatively low frequencies. Wave equation, which is similar to the Schr\"odinger equation, and wavelength of the standing electromagnetic wave are also established by the author's analysis. For a relatively low energy this wavelength becomes equal to the de Broglie wavelength. Without any quantum conditions, the author made a formula similar to the Rydberg's formula, which can be applied to the all known atoms, neutrons and some hyperons.Comment: 12 pages, 7 figures, 3 tables, English and French abstrac

On a non-combinatorial definition of Stirling numbers

In Combinatorics Stirling numbers may be defined in several ways. One such definition is given in [1], where an extensive consideration of Stirling numbers is presented. In this paper an alternative definition of Stirling numbers of both kind is given. Namely, Stirling numbers of the first kind appear in the closed formula for the n-th derivative of ln x. In the same way Stirling numbers of the second kind appear in the formula for the n-th derivative of f(e^x), where f(x) is an arbitrary smooth real function. This facts allow us to define Stirling numbers within the frame of differential calculus. These definitions may be interesting because arbitrary functions appear in them. Choosing suitable function we may obtain different properties of Stirling numbers by the use of derivatives only. Using simple properties of derivatives we obtain here three important properties of Stirling numbers. First are so called two terms recurrence relations, from which one can easily derive the combinatorial meaning of Stirling numbers. Next we obtain expansion formulas of powers into falling factorials, and vise versa. These expansions usually serve as the definitions of Stirling numbers, as in [1]. Finally, we obtain the exponential generating functions for Stirling and Bell numbers. As a by product the closed formulas for the $n$-th derivative of the functions f(e^x) and f(ln x) are obtained

Recurrence Relations and Determinants

We examine relationships between two minors of order n of some matrices of n rows and n+r columns. This is done through a class of determinants, here called $n$-determinants, the investigation of which is our objective. We prove that 1-determinants are the upper Hessenberg determinants. In particular, we state several 1-determinants each of which equals a Fibonacci number. We also derive relationships among terms of sequences defined by the same recurrence equation independently of the initial conditions. A result generalizing the formula for the product of two determinants is obtained. Finally, we prove that the Schur functions may be expressed as $n$-determinants