No-Free-Lunch Theorems in the continuum

No-Free-Lunch Theorems state, roughly speaking, that the performance of all search algorithms is the same when averaged over all possible objective functions. This fact was precisely formulated for the first time in a now famous paper by Wolpert and Macready, and then subsequently refined and extended by several authors, always in the context of a set of functions with discrete domain and codomain. Recently, Auger and Teytaud have shown that for continuum domains there is typically no No-Free-Lunch theorems. In this paper we provide another approach, which is simpler, requires less assumptions, relates the discrete and continuum cases, and that we believe that clarifies the role of the cardinality and structure of the domain

Enriched MU-Calculi Module Checking

The model checking problem for open systems has been intensively studied in the literature, for both finite-state (module checking) and infinite-state (pushdown module checking) systems, with respect to Ctl and Ctl*. In this paper, we further investigate this problem with respect to the \mu-calculus enriched with nominals and graded modalities (hybrid graded Mu-calculus), in both the finite-state and infinite-state settings. Using an automata-theoretic approach, we show that hybrid graded \mu-calculus module checking is solvable in exponential time, while hybrid graded \mu-calculus pushdown module checking is solvable in double-exponential time. These results are also tight since they match the known lower bounds for Ctl. We also investigate the module checking problem with respect to the hybrid graded \mu-calculus enriched with inverse programs (Fully enriched \mu-calculus): by showing a reduction from the domino problem, we show its undecidability. We conclude with a short overview of the model checking problem for the Fully enriched Mu-calculus and the fragments obtained by dropping at least one of the additional constructs

Mixed Nash equilibria in selfish routing problems with dynamic constraints

AbstractWe study the problem of routing traffic through a congested network consisting of m parallel links, each having a certain speed. Moreover, we are given n selfish (non-cooperative) agents, each of them willing to route her own piece of traffic on exactly one link. Agents are selfish in that they only pick a link which minimize the delay of their own piece of traffic. In this context much effort has been lavished in the framework of mixed Nash equilibria where the agent’s routing choices are regulated by probability distributions, one for each agent, which let the system thus enter a steady state from which no agent is willing to unilaterally deviate. In this work we consider situations in which some agents have constraints on the routing choice: in a sense they are forbidden to route their traffic on some links. We show that at most one Nash equilibrium may exist and, in some cases with equal speed links and where each agent is forbidden to route on at most one link, we give necessary and sufficient conditions on its existence; these conditions correlate the traffic load of the agents. We consider also a dynamic behaviour of the network when the constraints may vary, in particular when a constraint is removed: we establish under which conditions the network is still in equilibrium. These conditions are all effective in the sense that, given a set of yes/no routing constraints on each link for each agent, we provide the probability distributions corresponding to the unique Nash equilibrium associated to the constraints (if it exists). Moreover these conditions and the possible Nash equilibrium are computed in time O(mn)

Decompositions of Triangle-Dense Graphs

High triangle density -- the graph property stating that a constant fraction of two-hop paths belong to a triangle -- is a common signature of social networks. This paper studies triangle-dense graphs from a structural perspective. We prove constructively that significant portions of a triangle-dense graph are contained in a disjoint union of dense, radius 2 subgraphs. This result quantifies the extent to which triangle-dense graphs resemble unions of cliques. We also show that our algorithm recovers planted clusterings in approximation-stable k-median instances.Comment: 20 pages. Version 1->2: Minor edits. 2->3: Strengthened {\S}3.5, removed appendi

La vibrante bellezza della materia. La pandemia come occasione di disvelamento della materialità educativa

The pandemic has triggered changes that from a pedagogical point of view can be interpreted as accelerators of the digitalization processes of education and intensifiers of educational problems that have existed for some time. The pandemic scenario, despite its criticality, also represents a precious opportunity to unveil social and material assemblage that characterizes educational practices in their daily occurrence. In fact, in the current emergency, it is precisely that materiality made up of bodies, spaces, objects, rituals, affects, physical proximity that returns to prominence and to which we were not used to paying attention and that remained invisible, as it was taken for granted. The paper therefore intends to question the pedagogical and epistemological implications connected to the recovery of a gaze capable of reading educational materiality, in order to understand the transformations underway and to orient them towards sustainable educational futures

DesyreML: a SysML profile for heterogeneous embedded systems

International audienceWe propose a novel language for the formal description of heterogeneous embedded systems (DesyreML). As the main contribution, the language is formally described in terms of semantics and concrete syntax based on the SysML language. We define the concept of thick connector to allow for heterogeneous components communication and computation for multiple semantic domains (synchronous reactive, continuous time, discrete time, discrete-event). As technological application, a verification flow based on model-transformation techniques is described showing the use of an enriched version of the SystemC-AMS simulation kernel that is capable of simulating heterogeneous systems containing combinatorial loops. Finally, the language and the analysis flow are applied to a cruise control case study

Evaluation of driving performance after a transition from automated to manual control: a driving simulator study

n/