PIPages
Labs

Chun-Hung Liu

Texas A&M University-College Station, TX·Mathematics & Statistics·Early-career

Graphs are networks of points joined by links. They model road systems, computer networks, molecules and social ties, and they also record the distance between any two points.

Fields

Mathematics & Statistics

Computer Science

Topics

structural graph theory

asymptotic dimension

graph minors

Grants
1 known grant, through Jun 2027

What they work on

  1. Develop new structural theorems for minor-closed graph families, classes closed under deleting and contracting edges, and use them to attack embedding problems for the metric spaces these graphs support.
  2. Prove decomposition theorems for graph classes with polynomial expansion, a kind of sparse graph class, that avoid separator theory, the usual tool for cutting graphs into balanced parts.
  3. Determine where graph classes with finite asymptotic dimension, a measure of large-scale shape, fall in the hierarchy of sparse graph classes, using the new decomposition theorems.
  4. Extend graph minor theory from sparse to dense graphs within induced graph minor theory, drawing on notions inspired by asymptotic dimension and metric geometry.

More about the research

A long-standing question in mathematics is what large-scale shape such networks and spaces can have. Asymptotic dimension is a way of measuring that shape from far away, and it matters in metric geometry (the study of distance), in geometric group theory and in distributed computing. The PI and collaborators recently used structural graph theory to prove results about asymptotic dimension. Structural graph theory describes how complicated graphs are built from simpler pieces. This project proposes new structural theorems of this kind and aims to use them on open problems in combinatorics, theoretical computer science and geometry.

Why it matters

The project is basic mathematics. New structural theorems about graphs could resolve open questions linking combinatorics, metric geometry and theoretical computer science. They could also inform algorithmic problems such as embedding network distances into simpler spaces, and the study of sparse network classes used in computing.

Known grants

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

CAREER: Graph Structural Theorems, Asymptotic Dimension, and Beyond

NSF · Jul 2022 – Jun 2027

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Andrew Marks

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Investigate Weiss's question on whether amenability implies hyperfiniteness, meaning whether actions of orderly groups can be built from finite pieces, using Gromov's theory of asymptotic dimension, with applications to topological dynamics and operator algebras.

The school

Texas A&M University-College Station: 23 labs on PI Pages, $1.4B a year on research, 768 research doctorates a year.

More about Texas A&M University-College Station

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