We prove that Multicut in directed graphs, parameterized by the size of the cutset, is W [1]-hard and hence unlikely to be fixed-parameter tractable even if restricted to instances with only four terminal pairs. This negative result almost completely resolves one of the central open problems in the area of parameterized complexity of graph separation problems, posted originally by Marx and Razg...

Kingsbury, David T. (Naval Medical Research Institute, Bethesda, Md.). Bacteriocin production by strains of Neisseria meningitidis. J. Bacteriol. 91:1696-1699. 1966.-Strains of Neisseria meningitidis produce substances inhibitory to other strains of meningococcus. These substances are nontransmissible and show a high degree of strain specificity. The properties of one of these substances resemb...

We obtain a polynomial type upper bound for the size of the integral solutions of Thue equations F (X,Y ) = b defined over a totally real number field K, assuming that F (X, 1) has a root α such that K(α) is a CM-field. Furthermore, we give an algorithm for the computation of the integral solutions of such an equation.

We compare observations of the eclipsing binary system CM Draconis (hereafter CM Dra) with synthetic spectra computed using the stellar atmosphere code PHOENIX. High-resolution infrared spectroscopic observations of six 0.05-mm-wide regions between 1.51 and 2.45mm, combined with previous work, particularly CM Dra’s accurately known surface gravity, enable us to estimate its metallicity using de...

2 CM points on quaternion algebras 4 2.1 CM points, special points and reduction maps . . . . . . . . . 4 2.1.1 Quaternion algebras. . . . . . . . . . . . . . . . . . . . 4 2.1.2 Algebraic groups. . . . . . . . . . . . . . . . . . . . . . 5 2.1.3 Adelic groups. . . . . . . . . . . . . . . . . . . . . . . . 5 2.1.4 Main objects. . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.5 Galois action...