1 (a) Claim: R[X, Y ] is not a Euclidean domain. Proof: If R[X, Y ] was a Euclidean domain, then it would be a principal ideal domain. But consider I = (x, y) = (x) + (y). I is certainly not a principal ideal, as if it were, there would be some polynomial, g that divides everything in I, so g would divide x, implying that g does not contain any monomials with positive degree in y, and likewise ...

The science of human decision-making has long been a stronghold of psychologists. Among the voices that abound in the literature on how people make choices, one scholarly voice has remained strident through several decades. By studying human behavior through the lens of economics, Princeton University psychologist Daniel Kahneman has shown how inherent biases might influence our choices, overtl...

We study the homotopy types of complements of arrangements of n transverse planes in R, obtaining a complete classification for n ≤ 6, and lower bounds for the number of homotopy types in general. Furthermore, we show that the homotopy type of a 2-arrangement in R is not determined by the cohomology ring, thereby answering a question of Ziegler. The invariants that we use are derived from the c...

DAnIEL, parsimonious yet high-coverage multilingual epidemic surveillance DAnIEL is a multilingual epidemic surveillance system. DAnIEL relies on a parsimonious scheme making it possible to process new languages at small cost. MOTS-CLÉS : extraction d’information, recherche d’information, veille, multilinguisme, genre journalistique, grain caractère.