Dr. rer. nat. Sebastian Heinz

The mathematician works at the Weierstrass Institute for Applied Analysis and Stochastics (WIAS) in Berlin

Sebastian Heinz was born on September 26, 1977 in Berlin and studied mathematics at the Humboldt University of Berlin from 1998 till 2004. He received the Humboldt award of his university for his diploma thesis. He did his PhD (Dr. rer nat.) in 2008 at the same university within the Research Training Group 1128 “Analysis, Numerics, and Optimization of Multiphase Problems” sponsored by the DFG (Deutsche Forschungsgemeinschaft). His thesis work was nominated for the Adlershof Dissertation prize 2008. Since April 2008, he works in the DFG Research Unit 797 “Analysis and computation of microstructure in finite plasticity” at the Weierstrass Institute for Applied Analysis and Stochastics (WIAS) in Berlin.

His research focus

In his PhD thesis Sebastian Heinz was concerned with three classes of selected non-linear problems which are all subjects of research in the field of applied mathematics. These problems deal with

• the minimization of integrals in the calculus of variation,
• the solution of partial differential equations, and
• the solution of non-linear optimization calculations.

With the methods he applied many different applications can be covered in various fields of science, engineering and economics. As a practical example models of the non-linear elasticity theory were considered.

The aim of Sebastian’s thesis was to approximate a given non-linear problem by polynomial problems. In other words: A given non-linear problem is associated with a number of non-linear functions that serve as parameters and represent the non-linear problem. Polynomial approximation is of great interest, since much more mathematical tools are available which can be applied to polynomial problems than for non-polynomial (non-linear) problems in general.

As the main result Sebastian Heinz proofs that a given non-linear function can be approximated by polynomials so that the essential properties of the original function are preserved. In particular, this is true for quasi-convexity, a fundamental property in the calculus of variation, but difficult to be analyzed.

Contact: e-mail: heinz(at)wias-berlin.de