Multiplicities of eigenvalues of some linear search schemes

AbstractWe consider the problem of dynamically reorganizing a linear list when the list is subject to a random number of requests during a unit time interval. Three different heuristics are considered in which the selected items are moved to the front of the list in random order, the same order and finally the opposite order to the previous one. We find the eigenvalues and their multiplicities for the corresponding transition probability matrices. These are given in terms of the weights representing the probability of selection of the individual items. The methods employed are purely algebraic, being based on properties of permutations, and so our results are valid for arbitrary complex weights

Combinatorial Markov chains on linear extensions

We consider generalizations of Schuetzenberger's promotion operator on the set L of linear extensions of a finite poset of size n. This gives rise to a strongly connected graph on L. By assigning weights to the edges of the graph in two different ways, we study two Markov chains, both of which are irreducible. The stationary state of one gives rise to the uniform distribution, whereas the weights of the stationary state of the other has a nice product formula. This generalizes results by Hendricks on the Tsetlin library, which corresponds to the case when the poset is the anti-chain and hence L=S_n is the full symmetric group. We also provide explicit eigenvalues of the transition matrix in general when the poset is a rooted forest. This is shown by proving that the associated monoid is R-trivial and then using Steinberg's extension of Brown's theory for Markov chains on left regular bands to R-trivial monoids.Comment: 35 pages, more examples of promotion, rephrased the main theorems in terms of discrete time Markov chain

A musealização da memória fotográfica riograndina

Submitted by Jéssica Velho ([email protected]) on 2013-10-23T12:34:00Z No. of bitstreams: 1 A musealização da memória fotográfica riograndina.pdf: 272348 bytes, checksum: 4dff58486cc8d0bba92e68a074dfb029 (MD5)Approved for entry into archive by Gabriela Silva da Rosa ([email protected]) on 2013-10-23T20:17:41Z (GMT) No. of bitstreams: 1 A musealização da memória fotográfica riograndina.pdf: 272348 bytes, checksum: 4dff58486cc8d0bba92e68a074dfb029 (MD5)Made available in DSpace on 2013-10-23T20:17:41Z (GMT). No. of bitstreams: 1 A musealização da memória fotográfica riograndina.pdf: 272348 bytes, checksum: 4dff58486cc8d0bba92e68a074dfb029 (MD5) Previous issue date: 2012Este artigo busca analisar como se constitui o processo de musealização das fotografias doadas para a Fototeca Municipal Ricardo Giovannni, e como, nesse processo, as imagens se transformam em documentos/fontes de informação. Por meio de um levantamento documental da instituição e suas ações museológicas, pretende-se enfatizar a consolidação da Fototeca Municipal como um espaço museal propriamente dito. Desse modo, pretende-se ressaltar como a musealização desse acervo fotográfico em específico auxilia na preservação e na salvaguarda da memória rio-grandina.This paper aims to analyze how the process of musealization of photographs donated to the Fototeca Municipal Ricardo Giovannini, a photograph library in the city of Rio Grande, is constituted and how such process turns these images into documents/information sources. Through a documentary survey of the institution and its museum actions, it is intended to emphasize the consolidation this photograph library itself as a museum space. Thus, the way musealization of this photographic collection in particular helps preserve and safeguard the memory of Rio Grande is highlighted

La conquista spagnola di Castelnuovo e l'assedio ottomano (1538-39): Gutierre de Cetina, Luigi Tansillo ed Hernando de Herrera: le armi e la poesia.

Alla conquista spagnola (1538) di Castelnuovo (Herceg Novi), l'Impero ottomano rispose con veemenza, riconquistando la citt\ue0 nel 1539. I soldati di Barbarossa passarone per le armi i 3000 soldati spagnoli della guarnigione. Il fatto provoc\uf2 grande emozione e fu celebrato dai poeti-soldato Luigi Tansillo e Gutierre de Cetina e dal poeta di mestiere Hernando de Herrera