Date  Speaker  Topic 

Sept. 8  Organizational Meeting  
Sept. 22 
Université Félix HouphouëtBoigny 
On deltaBochner theorem Abstract: Let be a locally compact group, a large compact subgroup of and an arbitrary class of irreducible unitary representations of . 
Oct. 6  TBA  
Oct. 20 
Georgia Tech 
Frames via Unilateral Iterations of Bounded Operators Abstract: Dynamical Sampling is, in a sense, a hypernym classifying the set of inverse problems arising from considering samples of a signal and its future states under the action of a bounded linear operator. Recent works in this area consider questions such as when can a given frame for a separable Hilbert Space, , be represented by iterations of an operator on a single vector and what are necessary and sufficient conditions for a system, , to be a frame? In this talk, we will discuss the connection between frames given by iterations of a bounded operator and the theory of model spaces in the HardyHilbert Space as well as necessary and sufficient conditions for a system generated by the orbit of a pair of commuting bounded operators to be a frame. 
Nov. 3 
Tufts 
Topological Quantum Numbers We present a detailed spectral analysis for a new class of fractaltype diamond graphs, referred to as bubblediamond graphs, and provide a gaplabeling theorem in the sense of Bellissard for the corresponding probabilistic graph Laplacians using the technique of spectral decimation. Labeling the gaps in the Cantor set by the integrated density of states provides a set of topological quantum numbers that reflect the branching parameter of the graph construction and the decimation structure. The spectrum of the natural Laplacian on limit graphs is shown generically to be pure point supported on a Cantor set. However, one particular graph has a mixture of pure point and singularly continuous components. 
Nov. 17 
Tufts 

Dec. 1 
Tufts 
Inverse dynamic problem for 1D Dirac system on finite metric tree graphs. Leafpeeling method In the last years, the study of the Dirac operator on metric graphs has generated a 