493 research outputs found
pH-Impedance testing in gastro-oesophageal reflux
Gastro-Oesophageal Reflux Diseases
(GORD) are one of the most common
reasons for physician consultation. Out
of 2,056 individuals randomly surveyed
in the United States and Canada, up
to 35% had more than one upper
gastrointestinal symptom occurring
at least once per week with at least
moderate intensity.
Investigation of GORD has evolved
over the years.peer-reviewe
A Simply Exponential Upper Bound on the Maximum Number of Stable Matchings
Stable matching is a classical combinatorial problem that has been the
subject of intense theoretical and empirical study since its introduction in
1962 in a seminal paper by Gale and Shapley. In this paper, we provide a new
upper bound on , the maximum number of stable matchings that a stable
matching instance with men and women can have. It has been a
long-standing open problem to understand the asymptotic behavior of as
, first posed by Donald Knuth in the 1970s. Until now the best
lower bound was approximately , and the best upper bound was . In this paper, we show that for all , for some
universal constant . This matches the lower bound up to the base of the
exponent. Our proof is based on a reduction to counting the number of downsets
of a family of posets that we call "mixing". The latter might be of independent
interest
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