BNPA Education (British Paediatric Neurology Association) are running an event in our building in January and they need cloakroom volunteers on 9th and 10th January. They will pay £100 plus travel.
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The Vice-Chancellor’s Awards celebrate the dedication, courage, ambition and inspirational contributions of our people, and their commitment to excellence in pursuit of Oxford’s core mission (makes us sound good doesn't it?).
They recognise achievements and celebrate success – from our academics and researchers to professional, technical and support staff, whether they are in colleges, divisions, departments, central services, libraries, museums or elsewhere.
14:00
Efficient Adaptive Regularized Tensor Methods
Abstract
High-order tensor methods employing local Taylor approximations have attracted considerable attention for convex and nonconvex optimisation. The pth-order adaptive regularisation (ARp) approach builds a local model comprising a pth-order Taylor expansion and a (p+1)th-order regularisation term, delivering optimal worst-case global and local convergence rates. However, for p≥2, subproblem minimisation can yield multiple local minima, and while a global minimiser is recommended for p=2, effectively identifying a suitable local minimum for p≥3 remains elusive.
This work extends interpolation-based updating strategies, originally proposed for p=2, to cases where p≥3, allowing the regularisation parameter to adapt in response to interpolation models. Additionally, it introduces a new prerejection mechanism to discard unfavourable subproblem minimisers before function evaluations, thus reducing computational costs for p≥3.
Numerical experiments, particularly on Chebyshev-Rosenbrock problems with p=3, indicate that the proper use of different minimisers can significantly improve practical performance, offering a promising direction for designing more efficient high-order methods.
14:00
Categorical valuations for polytopes and matroids
Abstract
Valulations (of polytopes or matroids) are very useful and very mysterious. After taking some time to explain this concept, I will categorify it, with the aim of making it both more useful and less mysterious.