Research Areas

Computational Science
(Amundson, Dean, Glowinski, He, Kuznetsov, Pan, Sanders, Hoppe) The computational science program is currently the most active in the training of PhD students in our department. Graduates from this program are in demand in both industry and academia. This group runs a weekly interdisciplinary seminar.

The specialties in this group include numerical linear algebra (K), finite element methods for partial differential equations including domain decomposition methods and fictitious domain methods, optimal control and large scale optimization (D,G,H,Ho), computational fluid dynamics (D,G,H,Ho,K,P,S) and computer graphics (S).

There are many areas of computational science of interest to prospective graduate students:

Direct numerical simulation of particulate flow (D,G,H,K,P); large scale parallel computation for particulate flow in visco-elastic, Newtonian and non-Newtonian fluids (e.g., fluidization and sedimentation of solid particles (G,K,P) and electro- and magnetorheological fluids (Ho)); investigation of advanced interior-point optimization methods for the treatment of collisions (D,G) or in structural optimization (shape and topology optimization (Ho)); efficient parallel solvers for diffusion problems in heterogeneous anisotropic media (K); accurate numerical algorithms for geophysical electrodynamics (K); supersonic and hypersonic flows, particularly for spacecraft reentry simulation with equilibrium and non-equilibrium chemistry (S); computational electromagnetics and numerical methods for the simulation of flow in porous media (G,Ho,K); Molecular Dynamics with applications in materials science (Ho); biomimetics, in particular biotemplating (Ho); radiosity methods for global illumination in computer graphics (S).

 

Partial Differential Equations
The group is active in training PhD students and is a regular host of the Texas PDE Conference. Current research areas that involve students and postdocs include

  • Conservation Laws (Canic, Christoforou, Keyfitz, Wagner) Self-similar solutions of multidimensional problems: degenerate elliptic equations; classical solutions of free-boundary problems and the development of efficient numerical algorithms; existence theorems for systems of mixed type (coupled hyperbolic and elliptic equations); shock reflection problems~(Can, K; postdoc Kim). Vanishing viscosity solution to systems of conservation laws such as balance laws and non-local problems with fading memory; construction of admissible weak solutions as limits of viscous and self-similar viscous approximations. Continuous dependence of BV weak solutions on physical parameters; applications to Euler equations (Chr). Mathematical properties of nonhyperbolic equations: singular shocks; influence of viscosity~(K, Can; recent PhD student Reiff; current PhD student Mora). Reacting compressible flows; the dynamics of hyperelastic materials~(W).
  • Reaction-Diffusion Equations (Auchmuty,Fitzgibbon,Sanders). Well-posedness and a priori estimates, convergence of singular perturbations, and long-term dynamics of abstract nonlinear evolution equations, integral and partial integro-differential equations, and parabolic and elliptic systems~(F); Stefan-Maxwell diffusion, nonlinear boundary value problems, and Hamilton-Jacobi equations~(S); analysis of vortices and div-curl boundary value problems, and eigenvalue problems for operators of classical field theories and linear stability analyses~(A).
  • Models from Engineering, Ecology and Environment (Auchmuty,Fitzgibbon). A hybrid computational and analytical approach to developing models in population dynamics; spatially distributed ecological systems; spatio-temporal spread of infectious diseases; photo-chemical production and atmospheric dispersion of pollutants; rotating waves; and cardiac modeling~(A, F; recent PhD students Berry, Gross; current student Martynenko).

Modern Analysis
The Analysis Research Group has an excellent record of producing PhD students and placing them in research positions. The weekly functional analysis seminar is regularly attended by faculty from area universities. This seminar presents current research at a level accessible to graduate students and is often used as to present short courses. This group is a regular host of {the Functional Analysis Day} at which graduate students and postdocs from area universities present their research.

Specific areas of current research include:

  • C*-algebras associated to discrete and dynamical structures (Tomforde): This project involves associating C*-algebras to discrete and dynamical systems (e.g., graphs, matrices, bimodules, shift spaces) in order to study the structure of the C*-algebra and its relation to the defining system. It deals with the questions: When can a given C*-algebra be modeled as the C*-algebra of more than one type of discrete or dynamical system? Can one translate well-known properties of the system into properties of the associated C*-algebra? At what level of generality can one use these methods to model classifiable C*-algebras?
  • Classical field theories, particularly those of electromagnetics and mechanics (Auchmuty): Topics include representation theorems, trace and embedding theorems, analysis of linear operators, and variational principles. Related issues include nonconvex duality in the calculus of variations and convex analysis.
  • Operator spaces and completely bounded maps (Blecher,Paulsen): Operator spaces is a new area of functional analysis providing powerful tools with applications to unitary representations of groups, C*-algebras, von Neumann algebras, and operator theory.
  • Interpolation theory (Paulsen): existence and construction of functions, belonging to a special family, whose graphs pass through given data points. A typical application is the construction of an electrical circuit that at given frequencies has given responses.
  • Wavelet analysis (Papadakis): multiresolution theory, frame theory and sampling using techniques from functional and harmonic analysis. See Featured Project.

Dynamical Systems and Ordinary Differential Equations

The dynamical systems group specializes in systems with symmetry, ergodic theory, and applications. This group runs the weekly interdisciplinary Nonlinear Dynamics seminar jointly with colleagues in Physics and Engineering and has hosted many visitors and postdocs. Ian Stewart, University of Warwick, is an adjunct professor at UH and a frequent visitor.

Current theoretical interests include ergodic theory and central limit theorems, in particular for symmetric dynamical systems (F,T); the structure of symmetric attractors (F,G,S); coupled cell systems (F,G,J,S); generic properties of diffeomorphisms and flows including transitivity, ergodicity, and rapid mixing (F,T); classification of cocycles over actions of certain groups with application to rigidity properties (T); the extension of spectral theory for selfadjoint differential operators to the non-selfadjoint case (W).

Applications of equivariant dynamics include pattern formation (G,S,T), bursting (G,J), hypermeander of spirals based on ergodic-theoretic techniques in symmetric systems (F,T), and neuroscience (G,J,T).

Differential Geometry
Bao works on Riemann-Finsler geometry and its applications to the physical sciences. Current investigations concern constant curvature metrics (the space forms problem), and conformal deformations of Finsler metrics (encompassing issues from the existence of Ein\-stein-Finsler metrics to the flow of air traffic).

Topology
Friedberg studies topological algebra and topological semigroups, specifically the representation of uniquely divisible semigroups as cone-like structures and the representation of such semigroups by matrices.

Complex Geometry and Complex Analysis
Ji works on complex analysis and complex (CR) geometry. Current research is on the algebraicity problem of strongly pseudoconvex real analytic hypersurfaces and on proper holomorphic mappings between balls in different dimensional spaces (classification of such mappings, and estimate of degrees of rational maps).

Ru studies complex analysis and (complex hyperbolic) geometry. Topics include the geometric, function theoretic, and number theoretic properties associated with an algebraic variety and their connections. Faltings's work on the Fermat equation is a notable illustration of such questions.

Automated Discovery and Graph Theory
Fajtlowicz has developed GRAFFITI, an interactive computer program capable of making mathematical conjectures. This program generates conjectures in graph theory, number theory, and geometry. GRAFFITI has also made conjectures about fullerenes, the new form of carbon. Conjectures by GRAFFITI have inspired papers by mathematicians (Alon, Chung, and Kleitman), computer scientists, and chemists.

Both undergraduate and graduate students can do research based on GRAFFITI, either by continuing its development or by investigating conjectures generated by the program. The accessibility by undergraduates to original research is a special feature of this work.

Algebra
Fields of interest of the algebra group include number theory, group and module theory, rings and nearrings, lattice and abstract ideal theory, logic and foundations.

Hausen's research includes the relationship between algebraic structures and associated sets of mappings (e.g.~between groups and their automorphism groups). Current research topics include determining whether all nonzero abelian 2-groups with isomorphic automorphism groups are isomorphic; characterizing the rings $R$ such that every $R$-homogeneous map between any two nonsingular $R$-modules is a homomorphism; and generalizing the concept of $E$-rings and $E$-modules.

Kaiser studies lattices for logic and various versions of normality in the context of universal first order sentences, and epistemic logic (reasoning about knowledge). The department cross-lists his courses on automata and advanced graduate logic with Computer Science.

Financial Math
Financial mathematics is concerned with mathematical/statistical modeling and analysis of issues relating to risk management in the financial and energy markets. Kao's research interests include the applications of computational probability and statistics in pricing derivative products for risk management. His recent work have evolved around problems such as pricing NYMEX Gas Futures contracts, alternative approaches for valuation of spread options, Markov regime switching models for electricity spot prices, and volatility estimation and its implications in energy risk management.

Stochastic processes are a common model for systems whose past history influences but does not determine its future state. M. Nicol is interested in the theory and application of stochastic processes. For example, finding observations of Benford's law in many types of multiplicative stochastic processes, investigating the fine structure (such as Hausdorff dimension) of invariant measures for stochastic processes satisfying a contraction-on-average condition, and determining statistical behavior of models arising from economics, physics and biology, in particular, limit laws such as the central limit theorem and Brownian-motion like behavior in a wide variety of stochastic models.

Statistics
Decell's specialty is applied statistics: parameter and density estimation, statistical pattern recognition, the theory of generalized inverses, and statistical signal processing of remote sensing data. His expertise also includes applications to powered flight guidance and orbital mechanics.

Peters has interests in Bayesian statistics and deconvolution density estimation with applications in geology.

Mathematical Biology
There are several faculty members who have done work in mathematical biology, or whose work is directly applicable to mathematical biology. Please click here to find more information.

 

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