Coupled Fixed-Point Theorems for Contractions in Partially Ordered Metric Spaces and Applications

Bhaskar and Lakshmikantham (2006) showed the existence of coupled coincidence points of a mapping F from X×X into X and a mapping g from X into X with some applications. The aim of this paper is to extend the results of Bhaskar and Lakshmikantham and improve the recent fixed-point theorems due to Bessem Samet (2010). Indeed, we introduce the definition of generalized g-Meir-Keeler type contractions and prove some coupled fixed point theorems under a generalized g-Meir-Keeler-contractive condition. Also, some applications of the main results in this paper are given

Maximal Independent Sets for the Pixel Expansion of Graph Access Structure

Abstract : A visual cryptography scheme based on a given graph G is a method to distribute a secret image among the vertices of G, the participants, so that a subset of participants can recover the secret image if they contain an edge of G, by stacking their shares, otherwise they can obtain no information regarding the secret image. In this paper a maximal independent sets of the graph G was applied to propose a lower bound on the pixel expansion of visual cryptography schemes with graph access structure (G ). In addition a lower bound on the pixel expansion of basis matrices C5 and Peterson graph access structure were presented

Below the salt: a preliminary study of the dating and biology of five salt-preserved bodies from Zanjan Province, Iran

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