We present solutions of the holomorphic anomaly equations for compact two-parameter Calabi-Yau manifolds which are hypersurfaces in weighted projective space. In particular we focus on K3-fibrations where due to heterotic type II duality the topological invariants in the fibre direction are encoded in certain modular forms. The formalism employed provides holomorphic expansions of topological s...

in this paper, under appropriate oscillating behaviours of the nonlinear term, we prove some multiplicity results for a class of nonlinear fractional equations. these problems have a variational structure and we find three solutions for them by exploiting an abstract result for smooth functionals defined on a reflexive banach space. to make the nonlinear methods work, some careful analysis of t...

ABSTRACT Background: The radiographic image accuracy depends on the X-ray film information visibility. Good visibility is found by good contrast. Radiation exposure parameters (kVp, mAs) and film processing conditions have impact on contrast. In dentistry radiography machines, exposure time and processing procedure are set by radiographer. No optimized exposure time and process...

This is an expository paper discussing the regularity and large time behavior of admissible BV solutions of genuinely nonlinear, strictly hyperbolic systems of two conservation laws. The approach will be via the theory of generalized characteristics.

There has been extensive work on the existence of periodic solutions for nonlinear second order autonomous differantial equations, but little work regarding the third order problems. The popular Poincare-Bendixon theorem applies well to the former but not the latter (see [2] and [3]). We give a necessary condition for the existence of periodic solutions for the third order autonomous system...

A very general class of Lagrangians which couple scalar fields to gravita-tion and matter in two spacetime dimensions is investigated. It is shown that a vector field exists along whose flow lines the stress-energy tensor is conserved , regardless of whether or not the equations of motion are satisfied or if any Killing vectors exist. Conditions necessary for the existence of Killing vectors ar...

We extend a structural result by A. Dress and M. Steel [3], to show that the three-state Perfect Phylogeny problem reduces in polynomial time to the classic 2-SAT problem. We also give a more expanded exposition of the proof of the structural result from [3]. We hope this note will encourage additional researchers to try to solve the central open question: finding simple efficient solutions to ...

We describe necessary and sufficient conditions for a region in R." to be invariant for (Glimm) solutions of the system of n conservation laws Ut + f(u)x = 0. We also make some observations about the invariance of such regions for certain finite difference approximations of solutions of systems of conservation laws.