Searcharxiv⌕ Search

arXiv subjects

Santanu Dey

Publications and source records attributed to Santanu Dey.

38 records · Page 3Linked to original sources

Standard dilations of q-commuting tuples

Here we study dilations of q-commuting tuples. In [BBD] the authors gave the correspondence between the two standard dilations of commuting tuples and here these results have been extended to q-commuting tuples. We are able to do this when q-coefficients `$q_{ij}$' are of modulus one. We introduce `maximal q-commuting subspace ' of a $n$-tuple of operators and `standard q-commuting dilation'. Our main result is that the maximal q-commuting subspace of the standard noncommuting dilation of q-commuting tuple is the `standard q-commuting dilation'. We also introduce q-commuting Fock space as the maximal q-commuting subspace of full Fock space and give a formula for projection operator onto this space. This formula for projection helps us in working with the completely positive maps arising in our study. The first version of the Main Theorem (Theorem 19) of the paper for normal tuples using some tricky norm estimates and then use it to prove the general version of this theorem.

math.OA↗

Standard noncommuting and commuting dilations of commuting tuples

We introduce a notion called `maximal commuting piece' for tuples of Hilbert space operators. Given a commuting tuple of operators forming a row contraction there are two commonly used dilations in multivariable operator theory. Firstly there is the minimal isometric dilation consisting of isometries with orthogonal ranges and hence it is a noncommuting tuple. There is also a commuting dilation related with a standard commuting tuple on Boson Fock space. We show that this commuting dilation is the maximal commuting piece of the minimal isometric dilation. We use this result to classify all representations of Cuntz algebra O_n coming from dilations of commuting tuples.

math.OA↗