Galois action on the L-isogeny classes of abelian surfaces with quaternionic multiplication

E-print/Working paper (2013)

Galois level and congruence ideal for p-adic families of finite slope Siegel modular forms

in Compositio Mathematica (2019), 155(4), 776-831

We consider families of Siegel eigenforms of genus 2 and nite slope, de ned as local pieces of an eigenvariety and equipped with a suitable integral structure. Under some assumptions on the residual image ... [more ▼]

We consider families of Siegel eigenforms of genus 2 and nite slope, de ned as local pieces of an eigenvariety and equipped with a suitable integral structure. Under some assumptions on the residual image, we show that the image of the Galois representation associated with a family is big, in the sense that a Lie algebra attached to it contains a congruence subalgebra of non-zero level. We call Galois level of the family the largest such level. We show that it is trivial when the residual representation has full image. When the residual representation is a symmetric cube, the zero locus de ned by the Galois level of the family admits an automorphic description: it is the locus of points that arise from overconvergent eigenforms for GL2, via a p-adic Langlands lift attached to the symmetric cube representation. Our proof goes via the comparison of the Galois level with a \fortuitous" congruence ideal, that describes the zero- and one-dimensional subvarieties of symmetric cube type appearing in the family. We show that some of the p-adic lifts are interpolated by a morphism of rigid analytic spaces from an eigencurve for GL2 to an eigenvariety for GSp4. The remaining lifts appear as isolated points on the eigenvariety. [less ▲]

Galois representations and Galois groups over Q

in Bertin, Marie José; Bucur, Alina; Feigon, Brooke (Eds.) et al Women in Numbers Europe Research Directions in Number Theory (2015)

In this paper we generalize results of P. Le Duff to genus n hyperelliptic curves. More precisely, let C/Q be a hyperelliptic genus n curve and let J(C) be the associated Jacobian variety. Assume that ... [more ▼]

In this paper we generalize results of P. Le Duff to genus n hyperelliptic curves. More precisely, let C/Q be a hyperelliptic genus n curve and let J(C) be the associated Jacobian variety. Assume that there exists a prime p such that J(C) has semistable reduction with toric dimension 1 at p. We provide an algorithm to compute a list of primes l (if they exist) such that the Galois representation attached to the l-torsion of J(C) is surjective onto the group GSp(2n, l). In particular we realize GSp(6, l) as a Galois group over Q for all primes l in [11, 500000]. [less ▲]

Galois representations associated to classical modular forms of weight at least 2: Deligne's theorem

Presentation (2015, January 26)

Galois theory for sets of operations closed under permutation, cylindrification and composition

in Algebra Universalis (2012), 67(3), 273-297

A set of operations on A is shown to be the set of linear term operations of some algebra on A if and only if it is closed under permutation of variables, addition of inessential variables, and ... [more ▼]

A set of operations on A is shown to be the set of linear term operations of some algebra on A if and only if it is closed under permutation of variables, addition of inessential variables, and composition, and if it contains all projections. A Galois framework is introduced to describe the sets of operations that are closed under the operations mentioned above, not necessarily containing all projections. The dual objects of this Galois connection are systems of pointed multisets, and the Galois closed sets of dual objects are described accordingly. Moreover, the closure systems associated with this Galois connection are shown to be uncountable (even if the closed sets of operations are assumed to contain all projections). [less ▲]

The gambling craving experience questionnaire: Psychometric properties of a new scale based on the elaborated intrusion theory of desire

in Addictive Behaviors (2019), 95

Both research and clinical practice acknowledge the importance of craving as a maintenance and relapse factor in gambling disorder. The elaborated intrusion theory (EIT; Kavanagh et al., 2005) of desire ... [more ▼]

Both research and clinical practice acknowledge the importance of craving as a maintenance and relapse factor in gambling disorder. The elaborated intrusion theory (EIT; Kavanagh et al., 2005) of desire has been extensively investigated in relation to psychoactive substance or food cravings but, to date, has scarcely been studied in relation to gambling. In such a context, developing an assessment tool of gambling craving based on the EIT is warranted. To fill this gap in the literature, we aimed to develop and test the psychometric properties of a gambling-adapted version of the Craving Experience Questionnaire (CEQ; May et al., 2014), which is the best established measure of craving theoretically anchored in the EIT. An online survey that included the gambling CEQ (g-CEQ) and a craving induction procedure was administered to 274 community participants involved in gambling at least a few times a year. Concurrent and convergent validity were explored through correlations with a scale that measured gambling urge and with a series of questionnaires that measured disordered gambling symptoms, gambling cognitions, and gambling motives. The confirmatory factor analyses supported the validity of the expected three-factor model of the “strength” and “frequency” forms of the g-CEQ and showed better model fit than a one-factor solution, corroborating the initial structure of the CEQ. Furthermore, the scale has good internal consistency and its validity is supported by correlations with gambling-related constructs. The g-CEQ is thus a theoretically and psychometrically sound instrument to measure gambling craving based on the EIT. [less ▲]

Game character appeal in the eye of the beholder: The role of gendered perceptions

Scientific Conference (2016, June)

There are numerous studies on the stereotyped nature of video game characters, but knowledge is sparse on the nature of their appeal to players. Based on prior work in mass media research, this study ... [more ▼]

There are numerous studies on the stereotyped nature of video game characters, but knowledge is sparse on the nature of their appeal to players. Based on prior work in mass media research, this study examined the inclination to play characters of both genders in a third person action game. The results of an online survey with 245 respondents strongly suggested that the actual gender of the game character per se might not necessarily be indicative of its appeal to players, but rather players’ perceptions of the character’s gendered attributes, that is, how masculine or feminine they perceive the respective character. Findings prompt further research on perceptual and cognitive determinants of characters’ appeal for potentially shedding light on the gender gap in video game usage. [less ▲]

A Game of "Cut and Mouse": Bypassing Antivirus by Simulating User Inputs

in Proceedings of the 35th Annual Computer Security Applications Conference (2019)

To protect their digital assets from malware attacks, most users and companies rely on anti-virus (AV) software. But AVs' protection is a full-time task and AVs are engaged in a cat-and-mouse game where ... [more ▼]

To protect their digital assets from malware attacks, most users and companies rely on anti-virus (AV) software. But AVs' protection is a full-time task and AVs are engaged in a cat-and-mouse game where malware, e.g., through obfuscation and polymorphism, denial of service attacks and malformed packets and parameters, try to circumvent AV defences or make them crash. On the other hand, AVs react by complementing signature-based with anomaly or behavioral detection, and by using OS protection, standard code, and binary protection techniques. Further, malware counter-act, for instance by using adversarial inputs to avoid detection, et cetera. This paper investigates two novel moves for the malware side. The first one consists in simulating mouse events to control AVs, namely to send them mouse "clicks" to deactivate their protection. We prove that many AVs can be disabled in this way, and we call this class of attacks Ghost Control. The second one consists in controlling high-integrity white-listed applications, such as Notepad, by sending them keyboard events (such as "copy-and-paste") to perform malicious operations on behalf of the malware. We prove that the anti-ransomware protection feature of some AVs can be bypassed if we use Notepad as a "puppet" to rewrite the content of protected files as a ransomware would do. Playing with the words, and recalling the cat-and-mouse game, we call this class of attacks Cut-and-Mouse. [less ▲]

A Game Theoretic Analysis of the Twitter Follow-Unfollow Mechanism

in International Conference on Decision and Game Theory for Security (2018)

Twitter users often crave more followers to increase their social popularity. While a variety of factors have been shown to attract the followers, very little work has been done to analyze the mechanism ... [more ▼]

Twitter users often crave more followers to increase their social popularity. While a variety of factors have been shown to attract the followers, very little work has been done to analyze the mechanism how Twitter users follow or unfollow each other. In this paper, we apply game theory to modeling the follow-unfollow mechanism on Twitter. We first present a two-player game which is based on the Prisoner’s Dilemma, and subsequently evaluate the payoffs when the two players adopt different strategies. To allow two players to play multiple rounds of the game, we propose a multi-stage game model. We design a Twitter bot analyzer which follows or unfollows other Twitter users by adopting the strategies from the multi-stage game. We develop an algorithm which enables the Twitter bot analyzer to automatically collect and analyze the data. The results from analyzing the data collected in our experiment show that the follow-back ratios for both of the Twitter bots are very low, which are 0.76% and 0.86%. This means that most of the Twitter users do not cooperate and only want to be followed instead of following others. Our results also exhibit the effect of different strategies on the follow-back followers and on the non-following followers as well. [less ▲]

A Game Theoretic Approach to Multi-User Spectrum Allocation

in A Game Theoretic Approach to Multi-User Spectrum Allocation (2009)