We study covering codes of permutations with the l∞-metric. We provide a general code construction, which uses smaller building-block codes. We study cyclic transitive groups as building blocks, determining their exact covering radius, and showing linear-time algorithms for finding a covering codeword. We also bound the covering radius of relabeled cyclic transitive groups under conjugation. In...

In 2004, Sormani and Wei introduced the covering spectrum: a geometric invariant that isolates part of the length spectrum of a Riemannian manifold. In their paper they observed that certain Sunada isospectral manifolds share the same covering spectrum, thus raising the question of whether the covering spectrum is a spectral invariant. In the present paper we describe a group theoretic conditio...

Suppose that G is a definably connected, definable group in an ominimal expansion of an ordered group. We show that the o-minimal universal covering homomorphism p̃ : G̃ −→ G is a locally definable covering homomorphism and π1(G) is isomorphic to the o-minimal fundamental group π(G) of G defined using locally definable covering homomorphisms. ∗With partial support from the FCT (Fundação para a Ci...

background: although phototherapy has been used for more than 60 years it has some complications. the light waves produced from phototherapy reduce melatonin concentration in newborns with subsequent hypocalcemia. we aimed to assess the effect of head covering on calcium and magnesium levels in full term newborns during phototherapy. methods: in this randomized controlled trial, 72 full-term ic...