Geometry in Nature and Art

Nature displays an infinite array of geometric shapes from the small atom to the greatest of the spiral galaxies, crystalline solids, the honeycomb of the bee, snowflakes, the arrangement of seeds on sunflowers and pinecones, the spiral of the nautilus shell, the spider's web, and the regular polygons found in the basic shapes of many flowers are just a few of nature's geometric masterpieces.     

Elimination in Weyl Algebra and q-Identities

For the algorithmic proof of q-proper-hypergeometric identities, H.Wilf and D.Zeiberggave a theoretical frame work. In [1], they proved that q-proper-hypergeometric termssatisfy recurrence relations with polynomial coefficients and could obtain quite explicitbounds for the order of such a recurrence. But how can we find the recurrence relations?We consider single-variable q-proper-hypergeometric identities based on Zeilberg's basicidea. To find the recurrence relations, an elimination in the non-conuntative Weyl algebra     

Elimination in Weyl Algebra and Identities

In paper[1], Zeilberger presented an approach to sprcial functions identities, besdes     

Bifurcations and Chaos in Duffing Equation

The Duffing equation with even-odd asymmetrical nonlinear-restoring force and one external forcingis investigated.The conditions of existence of primary resonance,second-order,third-order subharmonics,m-order subharmonics and chaos are given by using the second-averaging method,the Melnikov method andbifurcation theory.Numerical simulations including bifurcation diagram,bifurcation surfaces and phase portraitsshow the consistence with the theoretical analysis.The numerical results also exhibit new dynamical behaviorsincluding onset of chaos,chaos suddenly disappearing to periodic orbit,cascades of inverse period-doublingbifurcations,period-doubling bifurcation,symmetry period-doubling bifurcations of period-3 orbit,symmetry-breaking of periodic orbits,interleaving occurrence of chaotic behaviors and period-one orbit,a great abundanceof periodic windows in transient chaotic regions with interior crises and boundary crisis and varied chaoticattractors.Our results show that many dynamical behaviors are strictly departure from the behaviors of theDuffing equation with odd-nonlinear restoring force.     

k-Factors and Spanning Subgraph in Graphs

In this paper, we discussed k-factors and spanning subgraph, and propose a conjecture which will lead to a series of important conclusion.     

K-Factors and Hamilton Cycles in Graphs

We discuss k-factors and Hamiltonian Graphs in graph theory. We prove a general version of the conjecture by R. Haggkvist; as a result, we prove two extended versions of two well-known theorems due to O. Ore and B. Jachson, respectively.     

σ-additivity in manuals and orthoalgebras

Notions of -additivity are introduced for orthoalgebras and for manuals. It is shown that the logic of a -additive manual is a -additive orthoalgebra, and that, conversely, every -additive orthoalgebra arises as such a logic. Using this theorem, it is shown that a given orthoalgebra admits at most one reasonable extension of its orthogonal sum operation to countable jointly orthogonal sets. It is also shown that every orthoalgebra can be embedded in a sigma-orthoalgebra and every orthomodular poset, in a -OMP.     

Rigidity and regularity in group actions

Some new results on the rigidity of automorphism groups and the regularity of(?)-Neumann operator in group actions are presented.     

Fekete and Szeg problem in one and higher dimensions

In this paper, we establish the Fekete and Szeg inequality for a class of holomorphic functions in the unit disk, and then we extend this result to a class of holomorphic mappings on the unit ball in a complex Banach space or on the unit polydisk in C~n.     

Bichromatic and Equichromatic Lines in ℂ2 and ℝ2

Let G and R each be a finite set of green and red points, respectively, such that |G|=n, |R|=n−k, G∩R=∅, and the points of G∪R are not all collinear. Let t be the total number of lines determined by G∪R. The number of equichromatic lines (a subset of bichromatic) is at least (t+2n+3−k(k+1))/4. A slightly weaker lower bound exists for bichromatic lines determined by points in ℂ². For sufficiently large point sets, a proof of a conjecture by Kleitman and Pinchasi is provided. A lower bound of (2t+14n−k(3k+7))/14 is demonstrated for bichromatic lines passing through at most six points. Lower bounds are also established for equichromatic lines passing through at most four, five, or six points.     

Singular Integrals and Commutators in Parabolic Herz Spaces and Their Applications

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Freezing and thawing processes in porous media – Experiment and Simulation

In this paper, a ternary macroscopic model has been presented with respect to the simulation of freeze-thaw cycles in liquid filled porous media. Regarding the detection of energetic effects during the phase transition a modified ansatz for the supply term of mass was discussed. The illustrated results of the example show that the simplified model is capable to predict experimental observations. Especially, the influence of the heat of fusion could be realized in an efficient manner. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

t-Sets and some algebraic properties in β S and in ℓ ∈ fty(S) *

For a large class of infinite discrete semigroups, we prove that right cancellative points in β S can have arbitrary norms or sizes. More precisely, if for x∈β S, we let ||x||= min{|A| : x ∈

Spaces over a Category and Assembly Maps in Isomorphism Conjectures in K‐ and L‐Theory

We give a unified approach to the Isomorphism Conjecture of Farrell and Jones on the algebraicKandLtheory of integral group rings and to the Baum–Connes Conjecture on the topologicalKtheory of reducedC*algebras of groups. The approach is through spectra over the orbit category of a discrete groupG.We give several points of view on the assembly map for a family of subgroups and characterize such assembly maps by a universal property generalizing the results of Weiss and Williams to the equivariant setting. The main tools are spaces and spectra over a category and their associated generalized homology and cohomology theories, and homotopy limits.     

Tautness and Fatou Components in ?2

Hyperbolicity played an important role in the classification of Fatou components for rational functions in the Riemann sphere. In higher dimensions Fatou components are not nearly as well understood. We investigate the Kobayashi completeness and tautness of invariant Fatou components for holomorphic endomorphisms of ?² and for Hénon mappings. We show that basins of attraction and domains with an attracting Riemann surface, previously known to be taut, are also complete, which is strictly stronger. We also prove tautness for a class of Siegel domains.     

Hypersurfaces in ℝn and critical points in their external region

In this paper we study the hypersurfaces given as connected compact regular fibers of a differentiable map , in the cases in which has finitely many nondegenerate critical points in the unbounded component of .     

Obstruction Theory and Coincidences in Positive Codimension

Let f, g ： X→Y be two maps between closed manifolds with dim X ≥ dim Y = n ≥ 3. We study the primary obstruction on（f, g） to deforming f and g to be coincidence free on the n-th skeleton of X. We give examples for which obstructions to deforming f and g to be coincidence free are detected by on （f, g）.     

Primes and Goldbach Numbers in Short Intervals

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