Automorphic Invariant Isometric Operators

作者：Bekker Miron B^*

来源：Complex Analysis and Operator Theory, 2009, 3(3): 587-610.

DOI：10.1007/s11785-008-0076-8

• Automorphic invariant isometry
• Mobius transformation
• characteristic operator-function
• contractive extension
• unitary extension

We consider isometric operators with finite defect numbers that are unitarily equivalent to their Mobius transformations. A functional characterization of such isometries is given in terms of their characteristic operator-functions. We show that any such isometry admits a contractive extension that is also unitarily equivalent to its Mobius transformation and a unitary extension in a larger space that has the same property. Examples of automorphic invariant operators are considered.

• 出版日期2009-10