BIRS Workshop 14w2199 July 11–13, 2014 Problem Solving Session

A companion event to the Lethbridge July 8–11 meeting Workshop on Algebraic Design Theory and Hadamard Matrices, the 2014 BIRS July 11–13 meeting Algebraic design theory with Hadamard matrices: applications, current trends and future directions, culminated in a lively problem session considering problems raised in both meetings.This session was unusually productive. By general consensus the problems posed comprise a provocative collection with great potential to incite new and interesting work. It captured well the elusive spirit generally sought in conference problem sessions: a mixture of on-the-spot group collaboration, instant insights and stubborn conundrums that could shift the focus of the general research community in helpful ways, reflecting the current state of the discipline and a snapshot of the kind of questions people are thinking about “on the ground” today. Perhaps most who attended went home having squirrelled away a problem or two from this session, to bring out on a rainy (or snowy) day.Several of the problems, with background information, were submitted in the form of brief notes for publication, and these are compiled here, edited somewhat for space. They represent a wide spectrum of both subject matter and types of queries. There are good problems for students to work on—being accessible and likely to hive off special cases for tractable small projects; and there are difficult research problems that will probably elude solutions in the foreseeable future.