In 2004, Agol proved the
Marden tameness conjecture, a conjecture of
Albert Marden. It states that a hyperbolic 3-manifold with finitely generated
fundamental group is
homeomorphic to the interior of a
compact 3-manifold. The conjecture was also independently proven by
Danny Calegari and
David Gabai, and implies the
Ahlfors measure conjecture. The conjecture (now theorem) states that every aspherical 3-manifold is finitely covered by a
Haken manifold. In 2022, he posted on the
ArXiv a proof of
Cameron Gordon's 1981 conjecture on
knot theory saying that ribbon concordance forms a partial ordering on the set of knots. ==Awards and honors==