PIPages
Labs

Simon Bortz

University of Alabama, AL·Mathematics & Statistics

Heat flow, diffusion and transport processes are described by parabolic partial differential equations, equations that track how a quantity spreads out over time. In real settings these processes happen in regions with complicated, rough edges, and those edges may even move over time.

Fields

Mathematics & Statistics

Topics

parabolic partial differential equations

parabolic PDE

heat equation

Grants
1 known grant, through Aug 2029

What they work on

  1. Characterize parabolic uniform rectifiability of time-varying boundaries through properties of caloric measure, the distribution of heat flowing in from the boundary, and through estimates for bounded solutions of the heat equation.
  2. Determine whether boundedness of certain parabolic singular integral operators can serve as a sharp test for parabolic uniform rectifiability of rough boundaries.
  3. Identify when caloric measure and surface measure on a rough time-dependent boundary are mutually absolutely continuous, meaning they agree on which boundary sets are negligible.
  4. Establish Green function estimates and quantitative absolute continuity of caloric measure for variable-coefficient parabolic operators in rough domains, and use them to solve Dirichlet and regularity problems under scale-invariant coefficient assumptions.

More about the research

This project asks a basic mathematical question: how does the shape and roughness of a region's boundary affect how solutions behave inside the region?

Why it matters

This is basic mathematics. It adds a clearer understanding of how rough, time-varying boundaries control the behavior of heat flow, diffusion and transport equations, and the tools it develops could eventually inform the analysis of these processes in complex or heterogeneous environments.

Known grants

From NIH and NSF research grants. Labs often have other funding we can't see.

Quantitative Parabolic Rectifiability, Parabolic Partial Differential Equations and Boundary Value Problems

NSF · Sep 2026 – Aug 2029

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Jiuyi Zhu

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Estimate the size of zero-level (nodal) sets of Laplacian eigenfunctions for second-order and higher-order elliptic equations, and determine how that size depends on high frequency.

The school

University of Alabama: 22 labs on PI Pages, $221M a year on research, 235 research doctorates a year.

More about University of Alabama

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