CARMA SEMINAR Location: Room V205, Mathematics Building (Callaghan Campus) The University of Newcastle Time and Date: 1:00 pm, Thu, 24th Sep 2015 Practice talks for the 2015 AustMS Meeting. Speaker: Mr Matthew Tam, School of Mathematical and Physical Sciences, The University of Newcastle Title: Reconstruction Algorithms for Blind Ptychographic Imaging      In scanning ptychography, an unknown specimen is illuminated by a localised illumination function resulting in an exit-wave whose intensity is observed in the far-field. A ptychography dataset is a series of these observations, each of which is obtained by shifting the illumination function to a different position relative to the specimen with neighbouring illumination regions overlapping. Given a ptychographic data set, the blind ptychography problem is to simultaneously reconstruct the specimen, illumination function, and relative phase of the exit-wave. In this talk I will discuss an optimisation framework which reveals current state-of-the-art reconstruction methods in ptychography as (non-convex) alternating minimization-type algorithms. Within this framework, we provide a proof of global convergence to critical points using the Kurdyka-Łojasiewicz property. Speaker: Assoc Prof Murray Elder, CARMA, The University of Newcastle Title: Using random walks to detect amenability in finitely generated groups      We use random walks to experimentally compute the first few terms of the cogrowth series for a finitely presented group. We propose candidates for the amenable radical of any non-amenable group, and a Følner sequence for any amenable group, based on convergence properties of random walks. Speaker: David Franklin, School of Mathematical and Physical Sciences, The University of Newcastle Title: Hardy Spaces and Paley-Wiener Spaces for Clifford-valued functions      The Hardy and Paley-Wiener Spaces are defined due to important structural theorems relating the support of a function's Fourier transform to the growth rate of the analytic extension of a function. In this talk we show that analogues of these spaces exist for Clifford-valued functions in n dimensions, using the Clifford-Fourier Transform of Brackx et al and the monogenic ($n+1$ dimensional) extension of these functions. [Permanent link]