ar X iv : m at h - ph / 0 31 00 10 v 1 8 O ct 2 00 3 Obstructions , Extensions and Reductions . Some applications of Cohomology ∗

ar X iv : m at h - ph / 0 30 70 15 v 1 8 J ul 2 00 3 Integrable geodesic flows on Riemannian manifolds : Construction and Obstructions ∗ Alexey

This paper is a review of recent and classical results on integrable geodesic flows on Riemannian manifolds and topological obstructions to integrability. We also discuss some open problems.

ar X iv : h ep - l at / 0 11 00 06 v 2 3 O ct 2 00 1 1 Matrix elements of ∆ S = 2 operators with Wilson fermions

ar X iv : m at h - ph / 0 31 10 01 v 3 6 O ct 2 00 4 Clifford Valued Differential Forms , Algebraic Spinor Fields , Gravitation , Electromagnetism and ” Unified ” Theories ∗

ar X iv : h ep - l at / 0 11 00 06 v 1 2 O ct 2 00 1 1 Matrix elements of ∆ S = 2 operators with Wilson fermions

ar X iv : m at h - ph / 0 11 00 12 v 1 9 O ct 2 00 1 Functional Equations and Poincare Invariant Mechanical Systems

We study the following functional equation that has arisen in the context of mechanical systems invariant under the Poincaré algebra: