The integer equal flow problem is an NP-hard network flow problem, in which all arcs in given sets R1, . . . , R` must carry equal flow. We show that this problem is effectively inapproximable, even if the cardinality of each set Rk is two. When ` is fixed, it is solvable in polynomial time. © 2009 Elsevier B.V. All rights reserved.

By sequencing tens of millions of TCRa transcripts from naive mouse CD8 T cells, Genolet et al (2012) show that the TCRa repertoire is at least as diverse as the TCRb repertoire. This overturns a long held view in the field that recombination of the Tcra locus occurs in a co-ordinate sequential bidirectional manner that relies on proximity of Va and Ja gene segments. The observation that rearra...

The year 2013 can aptly be called the “year of genes” at the Supreme Court. From the Monsanto gene patents case1 to the genetic fingerprinting of arrestees,2 the Court grappled with difficult questions arising out of an increasing application of genetics to various aspects of our society. Then came Association for Molecular Pathology v. Myriad Genetics, Inc., the muchpublicized case involving t...

Let M be a C-smooth strictly convex closed surface in R and denote by H the set of points x in the exterior of M such that all the tangent segments from x to M have equal lengths. In this note we prove that if H is either a closed surface containing M or a plane, then M is an Euclidean sphere. Moreover, we shall see that the situation in the Euclidean plane is very different. 1 In the Euclidean...

We develop a method to approach the problem of describing the closure in topological vector spaces in analysis on Rn of a module over the polynomials or over the span of the exponentials with imaginary spectral parameter. The method is not restricted to a particular type of space or to cyclic modules. It is easy to apply and extends naturally to “mixed” versions. The results generalize and simp...

We consider the rewrite system Rμ with μx.M →μ M[x := μx.M] as its single rewrite rule, where the signature consists of the variable binding operator commonly denoted by μ, first-order symbols, which in this paper are restricted to a binary function symbol F, and possibly some constant symbols. This kernel system denoting recursively defined objects occurs in several contexts, e.g. it is the fr...