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- Svante Janson, Yannis C. Stamatiou, Malvina Vamvakari
- Random Struct. Algorithms
- 2000

We lower the upper bound for the threshold for random 3-SAT from 4.6011 to 4.596 through two different approaches, both giving the same result. (Assuming the threshold exists, as is generally believed but still not rigorously shown.) In both approaches, we start with a sum over all truth assignments that appears in an upper bound by Kirousis et al. to the… (More)

The problem of determining the unsatisfiability threshold for random 3-SAT formulas consists in determining the clause to variable ratio that marks the (experimentally observed) abrupt change from almost surely satisfiable formulas to almost surely unsatisfiable. Up to now, there have been rigorously established increasingly better lower and upper bounds to… (More)

- Alexis C. Kaporis, Lefteris M. Kirousis, Yannis C. Stamatiou, Malvina Vamvakari, Michele Zito
- Electronic Notes in Discrete Mathematics
- 2001

The problem of determining the unsatisfiability threshold for random 3-SAT formulas consists in determining the clause to variable ratio that marks the experimentally observed abrupt change from almost surely satisfiable formulas to almost surely unsatisfiable. Up to now, there have been rigorously established increasingly better lower and upper bounds to… (More)

- A. Kyriakoussis, Malvina Vamvakari
- Discrete Mathematics
- 2005

In this paper, we present generalization of matching extensions in graphs and we derive combinatorial interpretation of wide classes of orthogonal and q-orthogonal polynomials. Specifically, we assign general weights to complete graphs, cycles and chains or paths defining matching extensions in these graphs. The generalized matching polynomials of these… (More)

are a generalization of the binomial coefficients, to which they reduce as q tends toward 1. In this article, we give an expression that captures the asymptotic behavior of these coefficients using the saddle point method and compare it with an upper bound for them that we derive using elementary means. We then consider as a case study the case q = 1+z/m, z… (More)

- Dimitris Panaretos, George Tzavelas, Malvina Vamvakari, Demosthenes Panagiotakos
- International journal of food sciences and…
- 2017

In the last few years, the need for processing large amount of data in nutrition science was dramatically arose. This created the need to apply, primarily, advanced analytical research methods that could enable researchers to handle the large amount of information. Dietary pattern analysis is a commonly used approach to enable and incorporate this… (More)

- A. Kyriakoussis, Malvina Vamvakari
- Fundam. Inform.
- 2012

- Malvina Vamvakari
- Electronic Notes in Discrete Mathematics
- 2017

- A. Kyriakoussis, Malvina Vamvakari
- Axioms
- 2014

From Kemp [1], we have a family of confluent q-ChuVandermonde distributions, consisted by three members I, II and III, interpreted as a family of q-steady-state distributions from Markov chains. In this article, we provide the moments of the distributions of this family and we establish a continuous limiting behavior for the members I and II, in the sense… (More)

- A. Kyriakoussis, Malvina Vamvakari
- Discrete Mathematics
- 1999

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