Two knowledge-based methods for High-Performance Sense Distribution Learning

Knowing the correct distribution of senses within a corpus can potentially boost the performance of Word Sense Disambiguation (WSD) systems by many points. We present two fully automatic and language-independent methods for computing the distribution of senses given a raw corpus of sentences. Intrinsic and extrinsic evaluations show that our methods outperform the current state of the art in sense distribution learning and the strongest baselines for the most frequent sense in multiple languages and on domain-specific test sets. Our sense distributions are available at http://trainomatic.org

On certain submodules of Weyl modules for SO(2n+1,F) with char(F) = 2

For $k = 1, 2,...,n-1$ let $V_k = V(\lambda_k)$ be the Weyl module for the special orthogonal group G = \mathrm{SO}(2n+1,\F) with respect to the $k$-th fundamental dominant weight $\lambda_k$ of the root system of type $B_n$ and put $V_n = V(2\lambda_n)$. It is well known that all of these modules are irreducible when \mathrm{char}(\F) \neq 2 while when \mathrm{char}(\F) = 2 they admit many proper submodules. In this paper, assuming that \mathrm{char}(\F) = 2, we prove that $V_k$ admits a chain of submodules $V_k = M_k \supset M_{k-1}\supset ... \supset M_1\supset M_0 \supset M_{-1} = 0$ where $M_i \cong V_i$ for $1,..., k-1$ and $M_0$ is the trivial 1-dimensional module. We also show that for $i = 1, 2,..., k$ the quotient $M_i/M_{i-2}$ is isomorphic to the so called $i$-th Grassmann module for $G$. Resting on this fact we can give a geometric description of $M_{i-1}/M_{i-2}$ as a submodule of the $i$-th Grassmann module. When \F is perfect G\cong \mathrm{Sp}(2n,\F) and $M_i/M_{i-1}$ is isomorphic to the Weyl module for \mathrm{Sp}(2n,\F) relative to the $i$-th fundamental dominant weight of the root system of type $C_n$. All irreducible sections of the latter modules are known. Thus, when \F is perfect, all irreducible sections of $V_k$ are known as well

Trust, sociability and stock market participation

We investigate the effects of both trust and sociability for stock market participation, the role of which has been examined separately by existing finance literature. We use internationally comparable household data from the Survey of Health, Ageing and Retirement in Europe supplemented with regional information on generalized trust from the World Value Survey and on specific trust to financial institutions from Eurobarometer. We show that trust and sociability have distinct and sizeable positive effects on stock market participation and that sociability is likely to partly balance the discouragement effect on stockholding induced by low generalized trust in the region of residence. We also show that specific trust in advice given by financial institutions represents a prominent factor for stock investing, compared to other tangible features of the banking environment. Probing further into various groups of households, we find that sociability can induce stockholding among the less well off in Sweden, Denmark, and Switzerland where stock market participation is widespread. On the other hand, the effect of generalized trust is strong in countries with limited participation and low average trust like Austria, Spain, and Italy, offering an explanation for the remarkably low participation rates of the wealthy living therein

Veronesean embeddings of dual polar spaces of orthogonal type

Given a point-line geometry P and a pappian projective space S,a veronesean embedding of P in S is an injective map e from the point-set of P to the set of points of S mapping the lines of P onto non-singular conics of S and such that e(P) spans S. In this paper we study veronesean embeddings of the dual polar space \Delta_n associated to a non-singular quadratic form q of Witt index n >= 2 in V = V(2n + 1; F). Three such embeddings are considered,namely the Grassmann embedding gr_n,the composition vs_n of the spin (projective) embedding of \Delta_n in PG(2n-1; F) with the quadric veronesean map of V(2n; F) and a third embedding w_n defined algebraically in the Weyl module V (2\lambda_n),where \lambda_n is the fundamental dominant weight associated to the n-th simple root of the root system of type Bn. We shall prove that w_n and vs_n are isomorphic. If char(F) is different from 2 then V (2\lambda_n) is irreducible and w_n is isomorphic to gr_n while if char(F) = 2 then gr_n is a proper quotient of w_n. In this paper we shall study some of these submodules. Finally we turn to universality,focusing on the case of n = 2. We prove that if F is a finite field of odd order q > 3 then sv_2 is relatively universal. On the contrary,if char(F) = 2 then vs_2 is not universal. We also prove that if F is a perfect field of characteristic 2 then vs_n is not universal,for any n>=2

Instabilities of microstate geometries with antibranes

One can obtain very large classes of horizonless microstate geometries corresponding to near-extremal black holes by placing probe supertubes whose action has metastable minima inside certain supersymmetric bubbling solutions. We show that these minima can lower their energy when the bubbles move in certain directions in the moduli space, which implies that these near-extremal microstates are in fact unstable once one considers the dynamics of all their degrees of freedom. The decay of these solutions corresponds to Hawking radiation, and we compare the emission rate and frequency to those of the corresponding black hole. Our analysis supports the expectation that generic non-extremal black holes microstate geometries should be unstable. It also establishes the existence of a new type of instabilities for antibranes in highly-warped regions with charge dissolved in fluxes.Comment: 24 pages, 4 figure