10 citations · 26 across the 11 of their papers we have counts for
11 papers
Real representations of semisimple Lie algebras have Q-forms
Dave Witte
We prove that each real semisimple Lie algebra G has a Q-form, such that every real representation of G can be realized over the rational numbers Q. This was previously proved by M…
Superrigid subgroups and syndetic hulls in solvable Lie groups
Dave Witte
This is an expository paper. It is not difficult to see that every group homomorphism from the additive group Z of integers to the additive group R of real numbers extends to a hom…
Transitive permutation groups of prime-squared degree
Edward Dobson, Dave Witte
We explicitly determine all of the transitive groups of degree p-squared, p a prime, whose Sylow p-subgroup is not the wreath product of two cyclic groups of order p. Furthermore,…
Groups that do not act by automorphisms of codimension-one foliations
Renato Feres, Dave Witte
Let G be a finitely generated group having the property that any action of any finite-index subgroup of G by homeomorphisms of the circle must have a finite orbit. (By a theorem of…
Homogeneous Lorentz manifolds with simple isometry group
Dave Witte
Let H be a closed, noncompact subgroup of a simple Lie group G, such that G/H admits an invariant Lorentz metric. We show that if G = SO(2,n), with n > 2, then the identity compone…
On automorphisms of arithmetic subgroups of unipotent groups in positive characteristic
Lucy Lifschitz, Dave Witte
Let F be a local field of positive characteristic, and let G be either a Heisenberg group over F, or a certain (nonabelian) two-dimensional unipotent group over F. If H is an arith…