Honest Doubt

Paul Hodgson
Institute for Advanced Study
November 17, 2010

Artist Paul Hodgson was a Director's Visitor at the Institute in 2010. In a Friends Forum, he discussed the "difficulties in making a judgement and dubtfulness in choosing one thing over another," that underlie his current practice and emerge "both in the way that I fabricate the work, and the images that I choose to present."

Planar Convexity, Infinite Perfect Graphs and Lipschitz Continuity

Menachem Kojman
Ben Gurion University of the Negev; Member, School of Mathematics
November 16, 2010

Infinite continuous graphs emerge naturally in the geometric analysis of closed planar sets which cannot be presented as countable union of convex sets. The classification of such graphs leads in turn to properties of large classes of real functions - e.g. the class of Lipschitz continuous functions - and to meta-mathematical properties of sub-ideals of the meager ideal (the sigma-ideal generated by nowhere dense sets over a Polish space) which reduce to finite Ramsey-type relations between random graphs and perfect graphs.

Fractional Perfect Matchings in Hypergraphs

Andrzej Rucinski
Adam Mickiewicz University in Polznan, Poland; Emory University
November 15, 2010

A perfect matching in a k-uniform hypergraph H = (V, E) on n vertices
is a set of n/k disjoint edges of H, while a fractional perfect matching
in H is a function w : E → [0, 1] such that for each v ∈ V we have
e∋v w(e) = 1. Given n ≥ 3 and 3 ≤ k ≤ n, let m be the smallest
integer such that whenever the minimum vertex degree in H satisfies
δ(H) ≥ m then H contains a perfect matching, and let m∗ be defined
analogously with respect to fractional perfect matchings. Clearly, m∗ ≤
m.

Configuration Spaces of Hard Discs in a Box

Matthew Kahle
Institute for Advanced Study
November 15, 2010

The "hard discs" model of matter has been studied intensely in statistical mechanics and theoretical chemistry for decades. From computer simulations it appears that there is a solid--liquid phase transition once the relative area of the discs is about 0.71, but little seems known mathematically. Indeed, Gian-Carlo Rota suggested that if we knew the total measure of the underlying configuration space, "we would know, for example, why water boils at 100 degrees on the basis of purely atomic calculations."

Panel Discussion: Secularism and Human Rights: Basic Human Rights in History, Philosophy, Political Science, and Sociology

Moderator: Harold Shapiro, President Emeritus and Professor of Economics and Public Affairs, Princeton University
Trustee, Institute for Advanced Study
November 13, 2010

Panelists:
Didier Fassin, James D. Wolfensohn Professor, School of Social Science
Jonathan Israel, Professor, School of Historical Studies
Avishai Margalit, George F. Kennan Professor, School of Historical Studies
Joan Wallach Scott, Harold F. Linder Professor, School of Social Science