**Date & Time:** Monday, May 21, 2010, 16:30-17:30.

**Venue:** Ramanujan Hall

**Title:** Some Applications of the Ping-Pong Lemma

**Speaker:** T. N. Venkataramanna, TIFR Mumbai

**Abstract:**
The ping-pong lemma of J. Tits gives a criterion for a subgroup of an
abstract group to be a free product of two smaller group. Using this
criterion, we construct Zariski dense discrete subgroups of the isometry group
of the hyperbolic *n*-space, which are of infinite covolume.