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Date Name
5/29/19 16:00Adam Přenosil (Vanderbilt University): Algebras of fractions: bimonoids and bimodules
Description:A classical result due essentially to Steinitz (1910) states that each cancellative commutative monoid can be embedded into an Abelian group. This was later improved by Ore (1931): each so-called right reversible cancellative monoid can be embedded into a group of right fractions, i.e. a group where each element has the form a . b-1 for some a; b in the original monoid. In this talk we show how to de_ne and construct algebras of fractions for other classes of algebras, such as Heyting algebras. These algebras of fractions will be involutive residuated lattices into which a given residuated lattice has a suitable embedding. We sketch two approaches to this problem: one based on bimonoids (one-sorted structures with two compatible monoidal operations) and one based on bimodules (in this context, two-sorted structures consisting of a monoid acting on another monoid). The talk is based on joint work with Nick Galatos and Costas Tsinakis.
www:https://web.cs.cas.cz/mku/appl/aktualni/aktualni.pdf
5/28/19 16:00Ján Antolík (Faculty of Mathematics and Physics, Charles University, Prague): Data-driven modelling of early visual system
Description:Neuroscience has produced a large body of data on the function and anatomy of brain but the transformation of this knowledge into a coherent understanding has been limited. Computational modeling can integrate such fragmented data into models of brain structures that satisfy the broad range of constraints imposed by experiments, thus advancing our understanding of their computational role, and their implementation in the neural substrate. In the first part of the lecture I will present a comprehensive multi-scale spiking model of cat primary visual cortex satisfying a range of anatomical, statistical and functional properties. It considers cortical layers 4 and 2/3, corresponding to a 5x5 mm patch of V1. We have subjected the model to numerous visual stimulation protocols covering a wide range of input statistics, from sparse noise to natural scenes with simulated eye-movements. The model expresses over multiple scales a number of statistical and functional properties previously identified experimentally including: spontaneous activity with a physiologically plausible resting conductance regime; contrast-invariant orientation-tuning width; realistic adaptive interplay between evoked excitatory and inhibitory conductances; center-surround interaction effects; and stimulus-dependent changes in the precision of the neural code as a function of input statistics. This data-driven model offers numerous insights into how the studied properties interact, and thus contributes to a better understanding of visual cortical dynamics.
www:http://cobra.cs.cas.cz/seminar
Please follow this link to the new website of the Institute of Computer Science ...