The present status of the period studies of cataclysmic variables is briefly reviewed, mainly from the observational point of view. A few comments on individual objects include EM Cyg, Z Cha, WZ Sge and AM CVn.

We present a new algorithm deciding for strings t and w whether w is an approximate generator of t with Levenshtein distance at most k. The algorithm is based on finite state transducers.

Interest in hurricane risk usually focuses on landfalling events of the highest intensity, which cause a disproportionate amount of hurricane-related damage. Yet assessing the long-term risk of the most intense landfalling events is problematic because there are comparatively few of them in the historical record. For this reason, return periods of the most intense storms are usually estimated b...

Motivated by recent developments in the computation of periods for string compactifications with c = 9, we develop a complementary method which also produces a convenient basis for related calculations. The models are realized as Calabi-Yau hypersurfaces in weighted projective spaces of dimension four or as Landau-Ginzburg vacua. The calculation reproduces known results and also allows a treatm...

We consider the set Γ (n) of all period sets of strings of length n over a finite alphabet. We show that there is redundancy in period sets and introduce the notion of an irreducible period set. We prove that Γ (n) is a lattice under set inclusion and does not satisfy the JordanDedekind condition. We propose the first enumeration algorithm for Γ (n) and improve upon the previously known asympto...