Departmental Colloquia Summer 2014

All colloquia (unless otherwise stated) will take place on Tuesdays at 4.00pm in Room 500 which is located on the 5th floor of the Mathematics Department.

See How to Find Us for further details. There will be tea afterwards in Maths Room 502. If you require any more information on the Departmental Colloquia please contact Prof Dima Vassiliev e-mail: d.vassiliev AT ucl.ac.uk or tel: 020-7679-2442.

17 June 2014

Gilbert Strang - MIT

Title: Matrices with banded inverses

Abstract:

Tridiagonal matrices (3 nonzero diagonals) are important in many applications. Sometimes they are the start of a full matrix that has to be completed - we don’t know the other entries but we can’t just put zeros. A special completion (it seems to be best possible) makes the **inverse** tridiagonal! Then there is a neat connection between the original matrix (before completion) and that inverse.

This extends to banded matrices and to wavelet matrices. There are some curious facts and undeveloped possibilities for banded matrices that have banded inverses.