4 papers
Lightweight Data Indexing and Compression in External Memory
Paolo Ferragina, Travis Gagie, Giovanni Manzini
In this paper we describe algorithms for computing the BWT and for building (compressed) indexes in external memory. The innovative feature of our algorithms is that they are light…
Tight Bounds for Online Stable Sorting
Travis Gagie, Yakov Nekrich
Although many authors have considered how many ternary comparisons it takes to sort a multiset of size , the best known upper and lower bounds still differ by a term linear…
Special symmetries of Banach spaces isomorphic to Hilbert spaces
Jarno Talponen
In this paper Hilbert spaces are characterized among Banach spaces in terms of transitivity with respect to nicely behaved subgroups of the isometry group. For example, the followi…
Superhedging in illiquid markets
Teemu Pennanen
We study contingent claims in a discrete-time market model where trading costs are given by convex functions and portfolios are constrained by convex sets. In addition to classical…