János Pach


János Pach is a mathematician and computer scientist working in the fields of combinatorics and discrete and computational geometry.

Biography

Pach was born and grew up in Hungary. He comes from a noted academic family: his father, :hu:Pach Zsigmond Pál|Zsigmond Pál Pach was a well known historian, and his uncle Pál Turán was one of the best known Hungarian mathematicians.
Pach received his Candidate degree from the Hungarian Academy of Sciences, in 1983, where his advisor was Miklós Simonovits.
Since 1977, he has been affiliated with the Alfréd Rényi Institute of Mathematics of the Hungarian Academy of Sciences.
He was Research Professor at the Courant Institute of Mathematical Sciences at NYU , Distinguished Professor of Computer Science at City College, CUNY, and Neilson Professor at Smith College.
In 2008, he joined École Polytechnique Fédérale de Lausanne as Professor of Mathematics.
He was the program chair for the International Symposium on Graph Drawing in 2004 and
Symposium on Computational Geometry in 2015. With Kenneth L. Clarkson and Günter Ziegler, he is co-editor-in-chief of the journal Discrete and Computational Geometry, and he serves on the editorial boards of several other journals including Combinatorica, SIAM Journal on Discrete Mathematics, Computational Geometry, Graphs and Combinatorics, Central European Journal of Mathematics, and Moscow Journal of Combinatorics and Number Theory.
He was an invited speaker at the Combinatorics session of the International Congress of Mathematicians, in Seoul, 2014.
also, He is an invited speaker at the 12th Winter School on Computational Geometry, in Tehran, Feb 2020.

Research

Pach has authored several books and over 200 research papers. He was one of the most frequent collaborators of Paul Erdős, authoring over 20 papers with him and thus has an Erdős number of one.
Pach's research is focused in the areas of combinatorics and discrete geometry.
In 1981, he solved Ulam's problem, showing that there exists
no universal planar graph.
In the early 90s
together with Micha Perles, he initiated the systematic study of extremal problems on topological and
geometric graphs.
Some of Pach's most-cited research work concerns the combinatorial complexity of families of curves in the plane and their applications to motion planning problems the maximum number of k-sets and halving lines that a planar point set may have, crossing numbers of graphs, embedding of planar graphs onto fixed sets of points, and lower bounds for epsilon-nets.

Awards and honors

Pach received the Grünwald Medal of the János Bolyai Mathematical Society, the Ford Award from the Mathematical Association of America, and the Alfréd Rényi Prize from the Hungarian Academy of Sciences. He was an Erdős Lecturer at Hebrew University of Jerusalem in 2005.
In 2011 he was listed as a fellow of the Association for Computing Machinery for his research in computational geometry.
In 2014 he was elected as a member of Academia Europaea, and in 2015 as a fellow of the American Mathematical Society "for contributions to discrete and combinatorial geometry and to convexity and combinatorics."

Books