a survey on the hover flies (diptera: syrphidae) fauna of northern iran, between 2010 and 2011, led to the discovery of the species pipiza accola violovitsh, 1985. both the genus and species are newly recorded from iran. all the specimens were collected from gilan and mazandaran provinces, using malaise traps. the diagnostic characters of p. accola and its geographical distribution is presented.

For all g ≥ 2 there is a Riemann surface of genus g whose automorphism group has order 8g+8, establishing a lower bound for the possible orders of automorphism groups of Riemann surfaces. Accola and Maclachlan established the existence of such surfaces; we shall call them Accola-Maclachlan surfaces. Later Kulkarni proved that for sufficiently large g the Accola-Maclachlan surface was unique for...

The regular coverings of regular affine algebraic maps are considered, and a large family of totally ramified coverings—the so-called Steinberg and Accola coverings—are fully classified.

We explore the structure of compact Riemann surfaces by studying their isometry groups. First we give two constructions due to Accola [1] showing that for all g ≥ 2, there are Riemann surfaces of genus g that admit isometry groups of at least some minimal size. Then we prove a theorem of Hurwitz giving an upper bound on the size of any isometry group acting on any Riemann surface of genus g ≥ 2...

We study SU(2) BPS monopoles with spectral curves of the form η + χ(ζ + bζ−1) = 0. Previous work has has established a countable family of solutions to Hitchin’s constraint that L was trivial on such a curve. Here we establish that the only curves of this family that yield BPS monopoles correspond to tetrahedrally symmetric monopoles. We introduce several new techniques making use of a factoriz...

We prove that the maximal number ag + b of automorphisms of equisymmetric and complex-uniparametric families of Riemann surfaces appearing in all genera is 4g+ 4. For each integer g ≥ 2 we find an equisymmetric complex-uniparametric family Ag of Riemann surfaces of genus g having automorphism group of order 4g + 4. For g ≡ −1mod4 we present another uniparametric family Kg with automorphism grou...