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Nov 27, 2016 at 14:08 comment added Yemon Choi Could you explain why you have accepted an answer which does not provide a "good" approximation of the shift? More generally, perhaps you should look at work of Steffen Roch and his coauthors which has a systematic look at "finite section methods" for approximating operators
Nov 21, 2016 at 20:47 vote accept Anton
Nov 29, 2016 at 21:04
Nov 21, 2016 at 7:39 answer added Denis Serre timeline score: 3
Nov 21, 2016 at 6:39 answer added David Ketcheson timeline score: 6
Nov 20, 2016 at 20:21 comment added Christian Remling Every $|z|<1$ is an eigenvalue with eigenvector $z^n$, so you could just take finitely many of these, truncate them, and make them eigenvectors of a finite-dimensional approximation. It's not so obvious though (to me) if these "approximations" still converge in the strong operator topology; perhaps this will depend on a suitable choice of the eigenvalues.
Nov 19, 2016 at 21:07 answer added T. Amdeberhan timeline score: 1
Nov 19, 2016 at 20:11 comment added Anton I am not sure what topology is suitable for this task, but would like to understand how to find finite-dimensional approximations which do not ignore continuous spectrum.
Nov 19, 2016 at 14:14 comment added David Handelman Google Berg's method. It's used for approximating the generators of irrational rotation algebras, one of which can be the shift.
Nov 19, 2016 at 14:14 comment added Tomasz Kania What kind of approximation do you have in mind? Certainly it is not possible in the norm topology.
Nov 19, 2016 at 14:09 history asked Anton CC BY-SA 3.0