#### Filter Results:

- Full text PDF available (16)

#### Publication Year

1990

2017

#### Publication Type

#### Co-author

#### Publication Venue

#### Key Phrases

Learn More

Let G be a connected reductive linear algebraic group. We use geometric methods to investigate G-completely reducible subgroups of G, giving new criteria for G-complete reducibility. We show that a subgroup of G is G-completely reducible if and only if it is strongly reductive in G; this allows us to use ideas of R.W. Richardson and Hilbert– Mumford–Kempf… (More)

- ACADEMISCH PROEFSCHRIFT, Benjamin Martin, T. G. Preuss
- 2013

- Christopher Mueller, Benjamin Martin, Andrew Lumsdaine
- APVIS
- 2007

In this study, we examine the use of graph ordering algorithms for visual analysis of data sets using visual similarity matrices. Visual similarity matrices display the relationships between data items in a dot-matrix plot format, with the axes labeled with the data items and points drawn if there is a relationship between two data items. The biggest… (More)

- Benjamin D Martin, John A Johansen, Scott G Edwards
- Hand clinics
- 2008

Simple elbow dislocations may present complications that are anything but simple. Although occurring less frequently, these complications are identical to those associated with more complex fracture-dislocations: contracture, heterotopic ossification, Essex-Lopresti injury, neurovascular injury, and residual instability. Each complication is discussed,… (More)

- Christopher Mueller, Benjamin Martin, Andrew Lumsdaine
- APVIS
- 2007

Visual similarity matrices (VSMs) are a common technique for visualizing graphs and other types of relational data. While traditionally used for small data sets or well-ordered large data sets, they have recently become popular for visualizing large graphs. However , our experience with users has revealed that large VSMs are difficult to interpret. In this… (More)

- MICHAEL BATE, BENJAMIN MARTIN, GERHARD RÖHRLE, RUDOLF TANGE
- 2007

Let G be a reductive linear algebraic group over an algebraically closed field of characteristic p > 0. A subgroup of G is said to be separable in G if its global and infinitesimal centralizers have the same dimension. We study the interaction between the notion of separability and Serre's concept of G-complete reducibility for subgroups of G. The… (More)

We give a short and uniform proof of a special case of Tits' Centre Conjecture using a theorem of J-P. Serre [8] and a result from [1]. We consider fixed point subcomplexes X H of the building X = X(G) of a connected reductive algebraic group G, where H is a subgroup of G.

- Michael Bate, Benjamin Martin, Gerhard R Ohrle, Rudolf Tange
- 2009

In this paper we consider various problems involving the action of a reductive group G on an affine variety V. We prove some general rationality results about the G-orbits in V. In addition, we extend fundamental results of Kempf and Hesselink regarding optimal destabilizing parabolic subgroups of G for such general G-actions. We apply our general… (More)

Let H be a reductive subgroup of a reductive group G over an algebraically closed field k. We consider the action of H on G n , the n-fold Cartesian product of G with itself, by simultaneous conjugation. We give a purely algebraic characterization of the closed H-orbits in G n , generalizing work of Richardson which treats the case H = G. This… (More)

- Benjamin Martin, Alexandre Goldsztejn, Laurent Granvilliers, Christophe Jermann
- SIAM J. Numerical Analysis
- 2013