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Algorithms for arithmetic groups with the congruence subgroup property (2014)
Journal Article
Detinko, A. S., Flannery, D. L., & Hulpke, A. (2015). Algorithms for arithmetic groups with the congruence subgroup property. Journal of Algebra, 421, 234-259. https://doi.org/10.1016/j.jalgebra.2014.08.027

© 2014 Elsevier Inc. We develop practical techniques to compute with arithmetic groups H≤SL(n,Q) for n>. 2. Our approach relies on constructing a principal congruence subgroup in H. Problems solved include testing membership in H, analyzing the subno... Read More about Algorithms for arithmetic groups with the congruence subgroup property.

Lattice gerbe theory (2014)
Journal Article
Lipstein, A. E., & Reid-Edwards, R. A. (2014). Lattice gerbe theory. Journal of High Energy Physics, 2014(9), Article ARTN 034. https://doi.org/10.1007/JHEP09%282014%29034

We formulate the theory of a 2-form gauge field on a Euclidean spacetime lattice. In this approach, the fundamental degrees of freedom live on the faces of the lattice, and the action can be constructed from the sum over Wilson surfaces associated wi... Read More about Lattice gerbe theory.

Integrality and arithmeticity of solvable linear groups (2014)
Journal Article
Detinko, A. S., Flannery, D. L., & de Graaf, W. A. (2015). Integrality and arithmeticity of solvable linear groups. Journal of Symbolic Computation, 68(P1), 138-145. https://doi.org/10.1016/j.jsc.2014.08.011

We develop a practical algorithm to decide whether a finitely generated subgroup of a solvable algebraic group G is arithmetic. This incorporates a procedure to compute a generating set of an arithmetic subgroup of G. We also provide a simple new alg... Read More about Integrality and arithmeticity of solvable linear groups.

Quantitative decision-making for the next generation of smarter evacuations (2014)
Book Chapter
Fry, J., Galla, T., & Binner, J. (2014). Quantitative decision-making for the next generation of smarter evacuations. In J. Preston, J. M. Binner, L. Branicki, T. Galla, N. Jones, J. King, …M. Smyrnakis (Eds.), City Evacuations: An Interdisciplinary Approach (63-87). Berlin: Springer. https://doi.org/10.1007/978-3-662-43877-0_4

In this chapter we discuss the mathematical modelling of the next generation of smarter evacuations. Alongside a burgeoning literature on resilience we formulate a quantitative decision-making framework through which Social Media can be used to deliv... Read More about Quantitative decision-making for the next generation of smarter evacuations.

Multivariate bubbles and antibubbles (2014)
Journal Article
Fry, J. (2014). Multivariate bubbles and antibubbles. European Physical Journal B : Condensed Matter and Complex Systems, 87, Article 174. https://doi.org/10.1140/epjb/e2014-50324-9

In this paper we develop models for multivariate financial bubbles and antibubbles based on statistical physics. In particular, we extend a rich set of univariate models to higher dimensions. Changes in market regime can be explicitly shown to repres... Read More about Multivariate bubbles and antibubbles.

On air cushioning in axisymmetric impacts (2014)
Journal Article
Moore, M., & Oliver, J. (2014). On air cushioning in axisymmetric impacts. IMA Journal of Applied Mathematics, 79(4), 661-680. https://doi.org/10.1093/imamat/hxu026

This paper extends the work of Moore et al. (2013, Air-cushioning in impact problems. IMA J. Appl. Math., 78, 818–838) by using a displacement potential formulation to analyse the post-impact effect of an air-cushioning layer on the normal impact of... Read More about On air cushioning in axisymmetric impacts.

The largest subsemilattices of the endomorphism monoid of an independence algebra (2014)
Journal Article
Araújo, J., Bentz, W., & Konieczny, J. (2014). The largest subsemilattices of the endomorphism monoid of an independence algebra. Linear algebra and its applications, 458, 60-79. https://doi.org/10.1016/j.laa.2014.05.041

An algebra A is said to be an independence algebra if it is a matroid algebra and every map α:X→A, defined on a basis X of A, can be extended to an endomorphism of A. These algebras are particularly well-behaved generalizations of vector spaces, and... Read More about The largest subsemilattices of the endomorphism monoid of an independence algebra.

Ising critical exponents on random trees and graphs (2014)
Journal Article
Dommers, S., Giardinà, C., & van der Hofstad, R. (2014). Ising critical exponents on random trees and graphs. Communications in mathematical physics, 328(1), 355-395. https://doi.org/10.1007/s00220-014-1992-2

We study the critical behavior of the ferromagnetic Ising model on random trees as well as so-called locally tree-like random graphs. We pay special attention to trees and graphs with a power-law offspring or degree distribution whose tail behavior i... Read More about Ising critical exponents on random trees and graphs.

Capillary and viscous perturbations to Helmholtz flows (2014)
Journal Article
Moore, M., Ockendon, H., Ockendon, J., & Oliver, J. (2014). Capillary and viscous perturbations to Helmholtz flows. Journal of Fluid Mechanics, 742, Article R1. https://doi.org/10.1017/jfm.2014.39

Inspired by recent calculations by Thoraval et al. (Phys. Rev. Lett., vol. 108, 2012, p. 264506) relating to droplet impact, this paper presents an analysis of the perturbations to the free surface caused by small surface tension and viscosity in ste... Read More about Capillary and viscous perturbations to Helmholtz flows.

Constraining isocurvature perturbations with the 21 cm emission from minihaloes (2014)
Journal Article
Takeuchi, Y., & Chongchitnan, S. (2014). Constraining isocurvature perturbations with the 21 cm emission from minihaloes. Monthly notices of the Royal Astronomical Society, 439(1), 1125-1135. https://doi.org/10.1093/mnras/stu059

We investigate the effects of isocurvature perturbations on the 21 cm radiation from minihaloes (MHs) at high redshifts and examine constraints on the isocurvature amplitude and power spectrum using the next generation of radio telescopes such as the... Read More about Constraining isocurvature perturbations with the 21 cm emission from minihaloes.

Taylor's modularity conjecture holds for linear idempotent varieties (2014)
Journal Article
Bentz, W., & Sequeira, L. (2014). Taylor's modularity conjecture holds for linear idempotent varieties. Algebra universalis, 71(2), 101-107. https://doi.org/10.1007/s00012-014-0273-4

The “Modularity Conjecture” is the assertion that the join of two nonmodular varieties in the lattice of interpretability types is nonmodular. We establish the veracity of this conjecture for the case of linear idempotent varieties. We also establish... Read More about Taylor's modularity conjecture holds for linear idempotent varieties.

Bubbles, shocks and elementary technical trading strategies (2014)
Journal Article
Fry, J. (2014). Bubbles, shocks and elementary technical trading strategies. European Physical Journal B : Condensed Matter and Complex Systems, 87, Article 1. https://doi.org/10.1140/epjb/e2013-40587-y

In this paper we provide a unifying framework for a set of seemingly disparate models for bubbles, shocks and elementary technical trading strategies in financial markets. Markets operate by balancing intrinsic levels of risk and return. This seeming... Read More about Bubbles, shocks and elementary technical trading strategies.

The effect of cosmic magnetic fields on the metagalactic ionization background inferred from the Lyman α forest (2013)
Journal Article
Chongchitnan, S., & Meiksin, A. (2014). The effect of cosmic magnetic fields on the metagalactic ionization background inferred from the Lyman α forest. Monthly notices of the Royal Astronomical Society, 437(4), 3639-3646. https://doi.org/10.1093/mnras/stt2169

The sources which reionized the intergalactic medium by redshift ̃6 are still unknown. A severe constraint on the ionization process is the low emissivity required to maintain the ionization in the Lya forest. Simulation-calibrated observations sugge... Read More about The effect of cosmic magnetic fields on the metagalactic ionization background inferred from the Lyman α forest.

Dualizability of automatic algebras (2013)
Journal Article
Bentz, W., Davey, B., Pitkethly, J., & Willard, R. (2014). Dualizability of automatic algebras. Journal of pure and applied algebra, 218(7), 1324-1345. https://doi.org/10.1016/j.jpaa.2013.11.020

We make a start on one of George McNulty's Dozen Easy Problems: “Which finite automatic algebras are dualizable?” We give some necessary and some sufficient conditions for dualizability. For example, we prove that a finite automatic algebra is dualiz... Read More about Dualizability of automatic algebras.

On the implementation of LIR: The case of simple linear regression with interval data (2013)
Journal Article
Cattaneo, M. E., & Wiencierz, A. (2014). On the implementation of LIR: The case of simple linear regression with interval data. Computational statistics, 29(3-4), 743-767. https://doi.org/10.1007/s00180-013-0459-9

This paper considers the problem of simple linear regression with interval-censored data. That is, n pairs of intervals are observed instead of the n pairs of precise values for the two variables (dependent and independent). Each of these inter... Read More about On the implementation of LIR: The case of simple linear regression with interval data.

Supernilpotence prevents dualizability (2013)
Journal Article
Bentz, W., & Mayr, P. (2014). Supernilpotence prevents dualizability. Journal of the Australian Mathematical Society, 96(01), 1-24. https://doi.org/10.1017/S1446788713000517

We address the question of the dualizability of nilpotent Mal’cev algebras, showing that nilpotent finite Mal’cev algebras with a nonabelian supernilpotent congruence are inherently nondualizable. In particular, finite nilpotent nonabelian Mal’cev al... Read More about Supernilpotence prevents dualizability.

Vibrations of a columnar vortex in a trapped Bose-Einstein condensate (2013)
Journal Article
Koens, L., Simula, T. P., & Martin, A. M. (2013). Vibrations of a columnar vortex in a trapped Bose-Einstein condensate. Physical review. A, 87(6), Article 063614. https://doi.org/10.1103/PhysRevA.87.063614

We derive a governing equation for a Kelvin wave supported on a vortex line in a Bose-Einstein condensate, in a rotating cylindrically symmetric parabolic trap, where it is assumed that the shape of the vortex line is dominated by the properties of t... Read More about Vibrations of a columnar vortex in a trapped Bose-Einstein condensate.

Air-cushioning in impact problems (2013)
Journal Article
Moore, M. R., Ockendon, J. R., & Oliver, J. M. (2013). Air-cushioning in impact problems. IMA Journal of Applied Mathematics, 78(4), 818-838. https://doi.org/10.1093/imamat/hxt026

This paper concerns the displacement potential formulation of the post-impact influence of an air-cushioning layer on the 2D impact of a liquid half-space by a rigid body. The liquid and air are both ideal and incompressible and attention is focussed... Read More about Air-cushioning in impact problems.

Conformal field theories in six-dimensional twistor space (2012)
Journal Article
Mason, L., Reid-Edwards, R., & Taghavi-Chabert, A. (2012). Conformal field theories in six-dimensional twistor space. Journal of Geometry and Physics, 62(12), 2353-2375. https://doi.org/10.1016/j.geomphys.2012.08.001

This article gives a study of the higher-dimensional Penrose transform between conformally invariant massless fields on space–time and cohomology classes on twistor space, where twistor space is defined to be the space of projective pure spinors of t... Read More about Conformal field theories in six-dimensional twistor space.