Non-polynomial Growth Research Articles

Existence and L∞-estimates for non-uniformly elliptic equations with non-polynomial growths

In the current paper, we investigate the existence and regularity of weak solutions to a class of non-uniformly elliptic equations with degenerate coercivity and non-polynomial growth. The model case is given as follows: div(exp(1 + |Du|)/(1 + |u|)2 Du) + M(|Du|)/(1 + |u|)2.u = f in ?. An L?- estimate of solutions is also obtained for an L1-datum f.

Classification of the pairs of matrices of fixed Jordan types and representations of bundles of semichains

We study the problem of classifying the pairs of matrices over an algebraically closed field with some restrictions on their Jordan canonical forms using earlier results of the first author. All tame and wild, polynomial and non-polynomial growth cases are described.

Adaptive output feedback control for large‐scale time‐delay systems with output‐dependent uncertain growth rate

SummaryIn this work, the problem of adaptive state regulation is addressed via output feedback for a wide class of large‐scale systems with strongly interconnected time‐delay nonlinearities. A design approach of partially decentralized adaptive controller is proposed, which gives a novel pair of reduced‐order observer and controller with nonidentifier‐based double adaptive gains. Compared with the existing results, the growth restrictions imposed on the interconnections are relaxed, where the growth rate includes not only an unknown constant but also the nonpolynomial functions of system output. The double dynamic gains are capable of compensating both the uncertain nonpolynomial growth rate and the unknown time‐varying delay. By constructing novel Lyapunov–Krasovskii functionals and combining dynamic‐scaling technique with 's lemma, it is shown that global adaptive state asymptotical regulation is achieved, that is all the closed‐loop signals are bounded, and the states of system and observer tend to zero as time goes to infinity. Finally, a simulation example is given to illustrate the proposed control scheme is independent of time delay and well universal.

On some nonlinear anisotropic elliptic equations in anisotropic Orlicz space

PurposeIn the present paper, the authors will discuss the solvability of a class of nonlinear anisotropic elliptic problems (P), with the presence of a lower-order term and a non-polynomial growth which does not satisfy any sign condition which is described by an N-uplet of N-functions satisfying the Δ2-condition, within the fulfilling of anisotropic Sobolev-Orlicz space. In addition, the resulting analysis requires the development of some new aspects of the theory in this field. The source term is merely integrable.Design/methodology/approachAn approximation procedure and some priori estimates are used to solve the problem.FindingsThe authors prove the existence of entropy solutions to unilateral problem in the framework of anisotropic Sobolev-Orlicz space with bounded domain. The resulting analysis requires the development of some new aspects of the theory in this field.Originality/valueTo the best of the authors’ knowledge, this is the first paper that investigates the existence of entropy solutions to unilateral problem in the framework of anisotropic Sobolev-Orlicz space with bounded domain.

On dual molecules and convolution-dominated operators

We show that sampling or interpolation formulas in reproducing kernel Hilbert spaces can be obtained by reproducing kernels whose dual systems form molecules, ensuring that the size profile of a function is fully reflected by the size profile of its sampled values. The main tool is a local holomorphic calculus for convolution-dominated operators, valid for groups with possibly non-polynomial growth. Applied to the matrix coefficients of a group representation, our methods improve on classical results on atomic decompositions and bridge a gap between abstract and concrete methods.

Two Tilts of Higher Spherical Algebras

We introduce and study two exotic families of finite-dimensional algebras over an algebraically closed field. We prove that every such an algebra is derived equivalent to a higher spherical algebra studied by Erdmann and Skowroński (Arch. Math. 114, 25–39, 2020), and hence that it is a tame symmetric periodic algebra of period 4. This together with the results of Erdmann and Skowroński (Algebr. Represent. Theor. 22, 387–406, 2019; Arch. Math. 114, 25–39, 2020) shows that every trivial extension algebra of a tubular algebra of type (2,2,2,2) admits a family of periodic symmetric higher deformations which are tame of non-polynomial growth and have the same Gabriel quiver, answering the question recently raised by Skowroński.

Quasilinear elliptic systems with right-hand side in divergence form

We study the existence of vector-valued solutions to quasilinear elliptic systems with nonpolynomial growth, namely N-functions. Existence of solutions is shown by means of the theory of Young measures, where the right-hand side is in the divergence form.

Existence and uniqueness of entropy solution of a nonlinear elliptic equation in anisotropic Sobolev–Orlicz space

Our objective in this paper is to study a certain class of anisotropic elliptic equations with the second term, which is a low-order term and non-polynomial growth; described by an N-uplet of N-function satisfying the $$\Delta _{2}$$ -condition in the framework of anisotropic Orlicz spaces. We prove the existence and uniqueness of entropic solution for a source in the dual or in $$L^{1}$$ , without assuming any condition on the behaviour of the solutions when x tends towards infinity. Moreover, we are giving an example of an anisotropic elliptic equation that verifies all our demonstrated results.

The Existence and Uniqueness of an Entropy Solution to Unilateral Orlicz Anisotropic Equations in an Unbounded Domain

The purpose of this work is to prove the existence and uniqueness of a class of nonlinear unilateral elliptic problem (P) in an arbitrary domain, managed by a low-order term and non-polynomial growth described by an N-uplet of N-function satisfying the Δ2-condition. The source term is merely integrable.

Variational inequality with almost history-dependent operator for frictionless contact problems

We study two quasistatic contact problems which describe the frictionless contact between a body and deformable foundation on an infinite time interval. The contact is modelled by the normal compliance condition with limited penetration and memory. The first problem deals with evolution of a body made of a viscoplastic material and in the second problem the material is viscoelastic with long memory. The constitutive functions of these materials have a non-polynomial growth. For each problem we derive a variational formulation that has the form of an almost history-dependent variational inequality for the displacement field. We demonstrate existence and uniqueness results of abstract almost history-dependent inclusion and variational inequality in the reflexive Orlicz–Sobolev space. Finally, we apply the abstract results to prove existence of the unique weak solution to the contact problems.

Algebraic entropy computations for lattice equations: why initial value problems do matter

In this letter we show that the results of degree growth (algebraic entropy) calculations for lattice equations strongly depend on the initial value problem that one chooses. We consider two problematic types of initial value configurations, one with problems in the past light-cone, the other one causing interference in the future light-cone, and apply them to Hirota’s discrete KdV equation and to the discrete Liouville equation. Both of these initial value problems lead to exponential degree growth for Hirota’s dKdV, the quintessential integrable lattice equation. For the discrete Liouville equation, though it is linearizable, one of the initial value problems yields exponential degree growth whereas the other is shown to yield non-polynomial (though still sub-exponential) growth. These results are in contrast to the common belief that discrete integrable equations must have polynomial growth and that linearizable equations necessarily have linear degree growth, regardless of the initial value problem one imposes. Finally, as a possible remedy for one of the observed anomalies, we also propose basing integrability tests that use growth criteria on the degree growth of a single initial value instead of all the initial values.

Adhesive contact problem for viscoplastic materials

We examine a mathematical model that describes a quasistatic adhesive contact between a viscoplastic body and deformable foundation. The material’s behaviour is described by the rate-type constitutive law which involves functions with a non-polynomial growth. The contact is modelled by the normal compliance condition with limited penetration and adhesion, a subdifferential friction condition also depending on adhesion, and the evolution of bonding field is governed by an ordinary differential equation. We present the variational formulation of this problem which is a system of an almost history-dependent variational–hemivariational inequality for the displacement field and an ordinary differential equation for the bonding field. The results on existence and uniqueness of solution to an abstract almost history-dependent inclusion and variational–hemivariational inequality in the reflexive Orlicz–Sobolev space are proved and applied to the adhesive contact problem.

Algebras of generalized quaternion type

We introduce and study the algebras of generalized quaternion type, being natural generalizations of algebras which occurred in the study of blocks of group algebras with generalized quaternion defect groups. We prove that all these algebras, with 2-regular Gabriel quivers, are periodic algebras of period 4 and very specific deformations of the weighted surface algebras of triangulated surfaces with arbitrarily oriented triangles. The main result of the paper forms an important step towards the Morita equivalence classification of all periodic symmetric tame algebras of non-polynomial growth. Applying the main result, we establish existence of wild periodic algebras of period 4, with arbitrary large number (at least 4) of pairwise non-isomorphic simple modules. These wild periodic algebras arise as stable endomorphism rings of cluster tilting Cohen-Macaulay modules over one-dimensional hypersurface singularities.

Elastic contact problem with Coulomb friction and normal compliance in Orlicz spaces

A static contact problem for inhomogeneous elastic materials is studied with a non-polynomial growth of the elasticity under the Coulomb’s law of dry friction and the normal compliance condition. We demonstrate the results on existence and uniqueness of a solution to an abstract subdifferential inclusion and a variational–hemivariational inequality in the reflexive Orlicz–Sobolev space which are applied to the static elastic frictional problem.

Weighted surface algebras

A finite-dimensional algebra A over an algebraically closed field K is called periodic if it is periodic under the action of the syzygy operator in the category of A-A-bimodules. The periodic algebras are self-injective and occurred naturally in the study of tame blocks of group algebras, actions of finite groups on spheres, hypersurface singularities of finite Cohen–Macaulay type, and Jacobian algebras of quivers with potentials. Recently, the tame periodic algebras of polynomial growth have been classified and it is natural to attempt to classify all tame periodic algebras. We introduce the weighted surface algebras of triangulated surfaces with arbitrarily oriented triangles and describe their basic properties. In particular, we prove that all these algebras, except the singular tetrahedral algebras, are symmetric tame periodic algebras of period 4. Moreover, we describe the socle deformations of the weighted surface algebras and prove that all these algebras are also symmetric tame periodic algebras of period 4. The main results of this paper form an important step towards a classification of all periodic symmetric tame algebras of non-polynomial growth, and lead to a complete description of all algebras of generalized quaternion type with 2-regular Gabriel quivers [36].

Convergence of a full discretization for a second-order nonlinear elastodynamic equation in isotropic and anisotropic Orlicz spaces

In this paper, we study a second-order, nonlinear evolution equation with damping arising in elastodynamics. The nonlinear term is monotone and possesses a convex potential but exhibits anisotropic and nonpolynomial growth. The appropriate setting for such equations is that of monotone operators in Orlicz spaces. Global existence of solutions in the sense of distributions is shown via convergence of the backward Euler scheme combined with an internal approximation. Moreover, we show uniqueness in a class of sufficiently smooth solutions and provide an a priori error estimate for the temporal semidiscretization.

On steady flow of non-Newtonian fluids with frictional boundary conditions in reflexive Orlicz spaces

A stationary viscous incompressible non-Newtonian fluid flow problem is studied with a non-polynomial growth of the extra (viscous) part of the Cauchy stress tensor together with a multivalued nonmonotone frictional boundary condition described by the Clarke subdifferential. We provide an abstract result on existence of solution to a subdifferential operator inclusion and a hemivariational inequality in the reflexive Orlicz–Sobolev space setting modeling the flow phenomenon. We establish the existence result, and under additional conditions, also uniqueness of a weak solution in the Orlicz–Sobolev space to the flow problem.

Hexagonal lattices with three-point interactions

We characterize the macroscopic effective behavior of hexagonal lattices with nonpolynomial growth, two-body interactions as well as angular interactions. The results apply to the mechanical behavior of atomic sheets, such as graphenes, with Lennard-Jones repulsive two-atomic energy and angular energy.

Simple geodesics and Markoff quads

The action of the mapping class group of the thrice-punctured projective plane on its $\mathrm{GL}(2,\mathbb{C})$ character variety produces an algorithm for generating the simple length spectra of quasi-Fuchsian thrice-punctured projective planes. We apply this algorithm to quasi-Fuchsian representations of the corresponding fundamental group to prove: a sharp upper-bound for the length of its shortest geodesic, a McShane identity and the surprising result of non-polynomial growth for the number of simple closed geodesic lengths.

Super-decomposable pure-injective modules over algebras with strongly simply connected Galois coverings

Assume that k is a field of characteristic different from 2, R is a strongly simply connected locally bounded k-category, G is an admissible group of k-linear automorphisms of R and A=R/G. We show that if A is not of polynomial growth, then there exists a special family of pointed A-modules, called an independent pair of dense chains of pointed modules. Then it follows by a result of M. Ziegler that there exists a super-decomposable pure-injective A-module, if the field k is countable. We also prove that if A is of non-polynomial growth and R does not contain a convex subcategory which is hypercritical or pg-critical, then there exists a factor algebra B of A such that B is a string algebra of non-polynomial growth. This fact is one of the key elements in the proof of our main results.