The MaxClique optimization problem cannot be approximated in polynomial-time within a ratio of n if NP 6= ZPP or within n if P 6= NP (H̊astad, 1999). We investigate the frequency with which approximation algorithms cannot achieve these ratios. Our results include the following for any ǫ > 0. 1. If NP 6= RP, then any polynomial-time approximation algorithm fails to approximate within n on a nonsp...

Address for correspondence: Prof. Luigi Macchia MD, PhD, Department and School of Allergology and Clinical Immunology, University of Bari – Aldo Moro, Piazza Giulio Cesare, Policlinico, 70124 Bari, Italy, phone: +39 080 5478817, fax: +39 080 5593688, e-mail: [email protected] Received: 30.01.2014, accepted: 29.04.2014 Long-term treatment of refractory severe chronic urticaria by omalizumab...

We construct a commutative algebra Ax of difference operators in R, depending on p + 3 parameters which is diagonalized by the multivariable Racah polynomials Rp(n; x) considered by Tratnik [27]. It is shown that for specific values of the variables x = (x1, x2, . . . , xp) there is a hidden duality between n and x. Analytic continuation allows us to construct another commutative algebra An in ...

We prove two results concerning approximate counting of independent sets in graphs with constant maximum degree ∆. The first implies that the Markov chain Monte Carlo technique is likely to fail if ∆ ≥ 6. The second shows that no fully polynomial randomized approximation scheme can exist for ∆ ≥ 25, unless RP = NP.

We show that every problem in the complexity class SZK (Statistical Zero Knowledge) is efficiently reducible to the Minimum Circuit Size Problem (MCSP). In particular Graph Isomorphism lies in RP. This is the first theorem relating the computational power of Graph Isomorphism and MCSP, despite the long history these problems share, as candidate NP-intermediate problems.

BACKGROUND The aim of this study was to estimate the prevalence of fibromyalgia, as well as to assess the major symptoms of this syndrome in an adult, low socioeconomic status population assisted by the primary health care system in a city in Brazil. METHODS We cross-sectionally sampled individuals assisted by the public primary health care system (n = 768, 35-60 years old). Participants were...

The voting rules proposed by Dodgson and Young are both designed to find the candidate closest to being a Condorcet winner, according to two different notions of proximity; the score of a given candidate is known to be hard to compute under both rules. In this paper, we put forward an LP-based randomized rounding algorithm which yields an O(logm) approximation ratio for the Dodgson score, where...

1 Central Animal Facility, Indian Institute of Science, Bangalore-560 012, India. 2 Anjuman Arts, Sciences & Commerce College, Bijapur-586101, India. 3 Research Centre, Electron Microscope Unit, # 5, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Kingdom of Saudi Arabia. 4 Centre for Sustainable Technologies, Indian Institute of Science, Bangalore-560 012, India. * Corre...

PURPOSE To quantify the internal free surface in various resin cements and glass-ionomer-based materials. MATERIALS AND METHODS Materials tested were Nexus fluid (NXF) and viscous (NXV), Vitremer (VTM), Fuji II LC (FII), Vitremer Luting Cement (VLC), Dyract (DYR) and Compoglass (COM). Samples (n=5) were made of each material between two microscopic glass slides under same weight. With a trans...