8,307 research outputs found
Coding Theory and Algebraic Combinatorics
This chapter introduces and elaborates on the fruitful interplay of coding
theory and algebraic combinatorics, with most of the focus on the interaction
of codes with combinatorial designs, finite geometries, simple groups, sphere
packings, kissing numbers, lattices, and association schemes. In particular,
special interest is devoted to the relationship between codes and combinatorial
designs. We describe and recapitulate important results in the development of
the state of the art. In addition, we give illustrative examples and
constructions, and highlight recent advances. Finally, we provide a collection
of significant open problems and challenges concerning future research.Comment: 33 pages; handbook chapter, to appear in: "Selected Topics in
Information and Coding Theory", ed. by I. Woungang et al., World Scientific,
Singapore, 201
Towards a collocation writing assistant for learners of Spanish
This paper describes the process followed in creating a tool aimed at helping learners produce collocations in Spanish. First we present the Diccionario de colocaciones del español (DiCE), an online collocation dictionary, which represents the first stage of this process. The following section focuses on the potential user of a collocation learning tool: we examine the usability problems DiCE presents in this respect, and explore the actual learner needs through a learner corpus study of collocation errors. Next, we review how collocation production problems of English language learners can be solved using a variety of electronic tools devised for that language. Finally, taking all the above into account, we present a new tool aimed at assisting learners of Spanish in writing texts, with particular attention being paid to the use of collocations in this language
-Schur functions and affine Schubert calculus
This book is an exposition of the current state of research of affine
Schubert calculus and -Schur functions. This text is based on a series of
lectures given at a workshop titled "Affine Schubert Calculus" that took place
in July 2010 at the Fields Institute in Toronto, Ontario. The story of this
research is told in three parts: 1. Primer on -Schur Functions 2. Stanley
symmetric functions and Peterson algebras 3. Affine Schubert calculusComment: 213 pages; conference website:
http://www.fields.utoronto.ca/programs/scientific/10-11/schubert/, updates
and corrections since v1. This material is based upon work supported by the
National Science Foundation under Grant No. DMS-065264
Connectivity for bridge-alterable graph classes
A collection of graphs is called bridge-alterable if, for each graph G with a
bridge e, G is in the class if and only if G-e is. For example the class of
forests is bridge-alterable. For a random forest sampled uniformly from
the set of forests on vertex set {1,..,n}, a classical result of Renyi (1959)
shows that the probability that is connected is .
Recently Addario-Berry, McDiarmid and Reed (2012) and Kang and Panagiotou
(2013) independently proved that, given a bridge-alterable class, for a random
graph sampled uniformly from the graphs in the class on {1,..,n}, the
probability that is connected is at least . Here we give
a more straightforward proof, and obtain a stronger non-asymptotic form of this
result, which compares the probability to that for a random forest. We see that
the probability that is connected is at least the minimum over of the probability that is connected.Comment: Amplified the discussion on raising the lower bound 2/5 to 1/
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