Abstract Let X be an irreducible, reduced complex projective hypersurface of degree d . A point P not contained in is called uniform if the monodromy group projection from isomorphic to symmetric $$S_d$$ S d We prove that locus non-uniform points finite when smooth or a...

Recent results in geometric invariant theory (GIT) for non-reductive linear algebraic group actions allow us to stratify quotient stacks of the form [X/H ], where X is a projective scheme and H is a linear algebraic group with internally graded unipotent radical acting linearly onX , in such a way that each stratum [S/H ] has a geometric quotient S/H . This leads to stratifications of moduli st...

Let X be a smooth projective surface such that linear and numerical equivalence of divisors on X coincide and let σ ⊆ |D| be a linear pencil on X with integral general fibers. A fiber of σ will be called special if either it is not integral or it has non-generic multiplicity at some of the base points (including the infinitely near ones) of the pencil. In this note we provide an algorithm to co...

Special covers are metacyclic covers of the projective line, with Galois group Z/p ⋊ Z/m, which have a specific type of bad reduction to characteristic p. Such covers arise in the study of the arithmetic of Galois covers of P with three branch points. Our results provide a classification of all special covers in terms of certain lifting data in characteristic p.

Let $G$ be a group and $pi(G)$ be the set of primes $p$ such that $G$ contains an element of order $p$. Let $nse(G)$ be the set of the number of elements of the same order in $G$. In this paper, we prove that the simple group $L_2(p^2)$ is uniquely determined by $nse(L_2(p^2))$, where $pin{11,13}$‎.‎

we consider the class $mathfrak m$ of $bf r$--modules where $bf r$ is an associative ring. let $a$ be a module over a group ring $bf r$$g$, $g$ be a group and let $mathfrak l(g)$ be the set of all proper subgroups of $g$. we suppose that if $h in mathfrak l(g)$ then $a/c_{a}(h)$ belongs to $mathfrak m$. we investigate an $bf r$$g$--module $a$ such that $g not = g'$, $c_{g}(a) = 1$. we stud...

In this paper we introduce a projective invarinat measure on the special unitary group. It is directly related to transition probabilities. It has some interesting connection with convex geometry. Applications to approximation of quantum circuits and entanglement are given.

There exists a duality between elliptic curves and noncommutative tori, i.e. C∗-algebras generated by the unitary operators u and v such that vu = euv. We show that this duality can be included into a general picture involving the algebraic curves of higher genus. In this way we prove that a big part of geometry of complex algebraic curves can be developed from the K-theory of a noncommutative ...