Wobbly double functors

Simple biset functors and double Burnside ring

Let G be a finite group and let k be a field. Our purpose is to investigate the simple modules for the double Burnside ring kB(G,G). It turns out that they are evaluations at G of simple biset functors. For a fixed finite group H, we introduce a suitable bilinear form on kB(G,H) and we prove that the quotient of kB(−, H) by the radical of the bilinear form is a semi-simple functor. This allows ...

Central Asia Grows Wobbly

Routine immunization: an essential but wobbly platform

Despite their vital role, routine immunization programs are taken for granted. Coverage levels are poor in some countries and have stagnated in others, while addition of new vaccines is an additional stressor. We need to strengthen: (1) policy processes, (2) monitoring and evaluation, (3) human resources, (4) regular delivery and supply systems, (5) local political commitment and ownership, (6)...

Out of the toolbox: toddlers differentiate wobbly and wooden handrails.

This study examined whether 16-month-old walking infants take the material composition of a handrail into account when assessing its effectiveness as a tool to augment balance. Infants were encouraged to cross from one platform to another via bridges of various widths (10, 20, 40 cm) with either a "wobbly" (foam or latex) or a wooden handrail available for assistance. Infants attempted to walk ...

Copower functors

We give a common generalization of two earlier constructions in [2], that yielded coalgebraic type functors for weighted, resp. fuzzy transition systems. Transition labels for these systems were drawn from a commutative monoid M or a complete semilattice L, with the transition structure interacting with the algebraic structure on the labels. Here, we show that those earlier signature functors a...