SDDs are Exponentially More Succinct than OBDDs

Introduced by Darwiche (2011), sentential decision diagrams (SDDs) are essentially as tractable as ordered binary decision diagrams (OBDDs), but tend to be more succinct in practice. This makes SDDs a prominent representation language, with many applications in artificial intelligence and knowledge compilation. We prove that SDDs are more succinct than OBDDs also in theory, by constructing a family of boolean functions where each member has polynomial SDD size but exponential OBDD size. This exponential separation improves a quasipolynomial separation recently established by Razgon (2013), and settles an open problem in knowledge compilation

Generic Expression Hardness Results for Primitive Positive Formula Comparison

We study the expression complexity of two basic problems involving the comparison of primitive positive formulas: equivalence and containment. In particular, we study the complexity of these problems relative to finite relational structures. We present two generic hardness results for the studied problems, and discuss evidence that they are optimal and yield, for each of the problems, a complexity trichotomy

Quantified Conjunctive Queries on Partially Ordered Sets

We study the computational problem of checking whether a quantified conjunctive query (a first-order sentence built using only conjunction as Boolean connective) is true in a finite poset (a reflexive, antisymmetric, and transitive directed graph). We prove that the problem is already NP-hard on a certain fixed poset, and investigate structural properties of posets yielding fixed-parameter tractability when the problem is parameterized by the query. Our main algorithmic result is that model checking quantified conjunctive queries on posets of bounded width is fixed-parameter tractable (the width of a poset is the maximum size of a subset of pairwise incomparable elements). We complement our algorithmic result by complexity results with respect to classes of finite posets in a hierarchy of natural poset invariants, establishing its tightness in this sense.Comment: Accepted at IPEC 201

First-Order Queries on Finite Abelian Groups

We study the computational problem of checking whether a logical sentence is true in a finite abelian group. We prove that model checking first-order sentences on finite abelian groups is fixed-parameter tractable, when parameterized by the size of the sentence. We also prove that model checking monadic second-order sentences on finite abelian groups finitely presented by integer matrices is not fixed-parameter tractable (under standard assumptions in parameterized complexity)

La mobilità in Piemonte nei primi anni del 2000

Quaderni di ricerca Ires ; n.110- Indice #3- Presentazione #5- Introduzione #7- La mobilità sistematica in Piemonte fra il 1991 e il 2001 #18- Le componenti sistemiche della mobilità in Piemonte #48- Appendici #79- Bibliografia #9

hereditary angioedema attack what happens to vasoactive mediators

Abstract Hereditary angioedema is a disabling, life-threatening condition caused by deficiency (type I) or dysfunction (type II) of the C1 inhibitor protein (C1-INH-HAE) leading to bradykinin accumulation and recurrent episodes of edema attack. Vascular leakage is a complex process sustained by the coordinated production of several permeabilizing factors including vascular endothelial growth factors (VEGFs), angiopoietins (ANGPTs) and phospholipase A2 enzymes (PLA2). We previously reported that patients with C1-INH-HAE in remission have increased plasma levels of VEGFs, ANGPTs and secreted PLA2. In this study, we sought to analyze plasma levels of these mediators in 15 patients with C1-INH-HAE during the acute attack compared to remission. Plasma concentrations of VEGF-A, VEGF-C and VEGF-D were not altered during attack compared to remission. Moreover, VEGF-D concentrations were not altered also in remission phase compared to controls. Concentrations of ANGPT1, a vascular stabilizer, were increased during attacks compared to symptoms-free periods, whereas ANGPT2 levels were not altered. The ANGPT2/ANGPT1 ratio was decreased during angioedema attacks. Platelet activating factor acetylhydrolase activity was increased in patients with C1-INH-HAE in remission compared to controls and was decreased during angioedema attacks. Our results emphasize the complexity by which several vasoactive mediators are involved not only in the pathophysiology of C1-INH-HAE, but also during angioedema attacks and its resolution