Dear Visitor,

this page is created in order to collect open problems in the theory of billiards that are considered to be important and interesting by today's researchers. This can be very helpful for interested people new to the topic, but also for most of the billiard people. It is also an opportunity for people having problems to communicate them towards a hopefully wide public. For this reason we invite everybody to send their contributions to one of us who maintain this web page:
Péter Bálint: bp@renyi.hu
Domokos Szász: szasz@math.bme.hu
Péter Tóth: mogy@math.bme.hu
We will add these contributions to our list with the name (and possibly address) of the sender indicated.

What do we mean under a Billiard?

How to locate (and submit) problems

List of problems
 

title	files	type of system	dim	investigated property	from (posted by)	date
The Boltzmann-Sinai Ergodic Hypothesis	.dvi .ps	finite, convex	HD	ergodicity	L. Boltzmann, Y. Sinai (Domokos Szász)	1970 (25. Jan. 2003)
Ergodic Hypothesis for Cylindric Billiards The Erdõtarcsa Conjecture	.dvi .ps	finite, convex	HD	ergodicity	N, Simányi, Domokos Szász (D. Szász)	2000 (25. Jan. 2003)
Can hyperbolicity of hard balls prevail over focusing boundary?	.dvi .ps	finite, mixed	2D	hyperbolicity, ergodicity	Michel Herman (Domokos Szász)	1996 (25. Jan. 2003)
Correlation decay in stadium-like billiards	.dvi .ps	finite, concave	HD	correlation decay	Péter Bálint	25. Jan. 2003
Softenings of dispersing billiards	.dvi .ps	finite, convex	2/H	hyperbolicity, ergodicity, correlation decay	Péter Bálint	25. Jan. 2003
Complexity property of singularities in high dimensions	.dvi .ps	finite, convex	HD	geometry	Péter Tóth	25. Jan. 2003
Fundamental Theorem for smooth billiards in high dimensions	.dvi .ps	finite, convex	HD	ergodicity	Péter Tóth	17. Feb. 2003
Decay of correlations for multi- dimensional dispersing billiards	.dvi .ps	finite, convex	HD	correlation decay	Péter Tóth	17. Feb. 2003