Border algorithms for computing Hasse diagrams of arbitrary lattices

Lattices are mathematical structures with many applications in computer science; among these, we are interested in fields like data mining, machine learning, or knowledge discovery in databases. One well-established use of lattice theory is in formal concept analysis (FCA), where the concept lattice with its diagram graph allows the visualization and summarization of data in a more concise representation. In the Data Mining community, the same mathematical notions (often under additional “frequency” constraints that bound from below the size of the support set) are studied under the banner of Closed-Set Mining. In these applications, each dataset consists of transactions, also called objects, each of which, besides having received a unique identifier, consists of a set of items or attributes taken from a previously agreed finite set. A concept is a pair formed by a set of transactions —the extent set or support set of the concept— and a set of attributes —the intent set of the concept— defined as the set of all those attributes that are shared by all the transactions present in the extent. Some data analysis processes are based on the family of all intents (the “closures” stemming from the dataset); but others require to determine also their order relation, which is a finite lattice, in the form of a line graph (the Hasse diagram).Peer Reviewe

Domain Theory 101 : an ideal exploration of this domain

Les problèmes logiciels sont frustrants et diminuent l’expérience utilisateur. Par exemple, la fuite de données bancaires, la publication de vidéos ou de photos compromettantes peuvent affecter gravement une vie. Comment éviter de telles situations ? Utiliser des tests est une bonne stratégie, mais certains bogues persistent. Une autre solution est d’utiliser des méthodes plus mathématiques, aussi appelées méthodes formelles. Parmi celles-ci se trouve la sémantique dénotationnelle. Elle met la sémantique extraite de vos logiciels préférés en correspondance avec des objets mathématiques. Sur ceux-ci, des propriétés peuvent être vérifiées. Par exemple, il est possible de déterminer, sous certaines conditions, si votre logiciel donnera une réponse. Pour répondre à ce besoin, il est nécessaire de s’intéresser à des théories mathématiques suffisamment riches. Parmi les candidates se trouvent le sujet de ce mémoire : la théorie des domaines. Elle offre des objets permettant de modéliser formellement les données et les instructions à l’aide de relations d’ordre. Cet écrit présente les concepts fondamentaux tout en se voulant simple à lire et didactique. Il offre aussi une base solide pour des lectures plus poussées et contient tout le matériel nécessaire à sa lecture, notamment les preuves des énoncés présentés.Bugs in programs are definitively annoying and have a negative impact on the user experience. For example, leaks of bank data or leaks of compromising videos or photos have a serious effect on someone’s life. How can we prevent these situations from happening? We can do tests, but many bugs may persist. Another way is to use mathematics, namely formal methods. Among them, there is denotational semantics. It links the semantics of your favorite program to mathematical objects. On the latter, we can verify properties, e.g., absence of bugs. Hence, we need a rich theory in which we can express the denotational semantics of programs. Domain Theory is a good candidate and is the main subject of this master thesis. It provides mathematical objects for data and instructions based on order relations. This thesis presents fundamental concepts in a simple and pedagogical way. It is a solid basis for advanced readings as well as containing all the needed knowledge for its reading, notably proofs for all presented statements