Sur le rapport de Hobbes au monarchisme, les études hobbesiennes font largement consensus : tout au long de sa vie, le théoricien du Léviathan aurait été, disent-elles, un monarchiste convaincu, fidèle à la dynastie anglaise des Stuart. Or le présent travail cherche à ébranler la rigueur de cette thèse traditionnelle. Acquis aux recherches contextualistes de J. Collins, qui ont déjà montré les affinités hobbesiennes à l’égard des politiques anticléricales de Cromwell, il souhaite montrer que de telles affinités dissimulent une intention politique beaucoup plus profonde, celle de la réalisation politique des principes moraux de la loi naturelle. Dans cette perspective, Hobbes serait, sous l’impulsion de la méthode résolutive-compositive, non seulement l’inventeur du premier droit naturel subjectif dans l’histoire de la philosophie politique, mais aussi le théoricien d’une loi naturelle inédite, édifiée sur la rationalité des volontés individuelles. Ainsi, par la publication du Léviathan en 1651, Hobbes n’aurait pas exprimé ses affinités politiques pour la monarchie anglaise renversée : il aurait plutôt dévoilé son projet politique d’instituer une souveraineté politique qui repose sur le consentement rationnel de tous les sujets. Monarchiste dans sa jeunesse, Hobbes serait alors devenu, en élaborant sa science politique, partisan d’un régime politique que l’on pourrait nommer démocratie de la raison positive. / On Hobbes’s relationship to the monarchy, Hobbes Studies make a general consensus: throughout his life, the theorist of the Leviathan would have been a convinced monarchist, faithful to the English dynasty of the Stuart. This work seeks to undermine the rigor of this traditional thesis. Inspired by the contextualist research of J. Collins, which have already shown the Hobbesian affinities towards the anticlerical policies of Cromwell, it wants to show that such affinities hide a much deeper political intention: the political realization of the moral principles of natural law. In this perspective, Hobbes would be, at the instigation of the resolutive-compositive method, not only the inventor of the first subjective natural right in the history of political philosophy, but also the theorist of a new natural law, built on the rationality of all individual wills. So, with the publication of the Leviathan in 1651, Hobbes would not have expressed his political affection for the overthrown English monarchy: he would rather have revealed his political project to establish a political sovereignty based on the rational consent of all subjects. Monarchist in his youth, Hobbes would then have become, with the elaboration of his political science, a supporter of a political system that could be named democracy of the positive rationality.

Sur le rapport de Hobbes au monarchisme, les études hobbesiennes font largement consensus : tout au long de sa vie, le théoricien du Léviathan aurait été, disent-elles, un monarchiste convaincu, fidèle à la dynastie anglaise des Stuart. Or le présent travail cherche à ébranler la rigueur de cette thèse traditionnelle. Acquis aux recherches contextualistes de J. Collins, qui ont déjà montré les affinités hobbesiennes à l’égard des politiques anticléricales de Cromwell, il souhaite montrer que de telles affinités dissimulent une intention politique beaucoup plus profonde, celle de la réalisation politique des principes moraux de la loi naturelle. Dans cette perspective, Hobbes serait, sous l’impulsion de la méthode résolutive-compositive, non seulement l’inventeur du premier droit naturel subjectif dans l’histoire de la philosophie politique, mais aussi le théoricien d’une loi naturelle inédite, édifiée sur la rationalité des volontés individuelles. Ainsi, par la publication du Léviathan en 1651, Hobbes n’aurait pas exprimé ses affinités politiques pour la monarchie anglaise renversée : il aurait plutôt dévoilé son projet politique d’instituer une souveraineté politique qui repose sur le consentement rationnel de tous les sujets. Monarchiste dans sa jeunesse, Hobbes serait alors devenu, en élaborant sa science politique, partisan d’un régime politique que l’on pourrait nommer démocratie de la raison positive. / On Hobbes’s relationship to the monarchy, Hobbes Studies make a general consensus: throughout his life, the theorist of the Leviathan would have been a convinced monarchist, faithful to the English dynasty of the Stuart. This work seeks to undermine the rigor of this traditional thesis. Inspired by the contextualist research of J. Collins, which have already shown the Hobbesian affinities towards the anticlerical policies of Cromwell, it wants to show that such affinities hide a much deeper political intention: the political realization of the moral principles of natural law. In this perspective, Hobbes would be, at the instigation of the resolutive-compositive method, not only the inventor of the first subjective natural right in the history of political philosophy, but also the theorist of a new natural law, built on the rationality of all individual wills. So, with the publication of the Leviathan in 1651, Hobbes would not have expressed his political affection for the overthrown English monarchy: he would rather have revealed his political project to establish a political sovereignty based on the rational consent of all subjects. Monarchist in his youth, Hobbes would then have become, with the elaboration of his political science, a supporter of a political system that could be named democracy of the positive rationality.

The study and recognition of graph families (or graph properties) is an essential part of combinatorics. Graph colouring is another fundamental concept of graph theory that can be looked at, in large part, as the recognition of a family of graphs that are colourable according to certain rules. In this thesis, we study additive induced-hereditary families, and some generalisations, from a colouring perspective. Our main results are: · Additive induced-hereditary families are uniquely factorisable into irreducible families. · If <i>P</i> and <i>Q</i> are additive induced-hereditary graph families, then (<i>P</i>,<i>Q</i>)-COLOURING is NP-hard, with the exception of GRAPH 2-COLOURING. Moreover, with the same exception, (<i>P</i>,<i>Q</i>)-COLOURING is NP-complete iff <i>P</i>- and <i>Q</i>-RECOGNITION are both in NP. This proves a 1997 conjecture of Kratochvíl and Schiermeyer. We also provide generalisations to somewhat larger families. Other results that we prove include: · a characterisation of the minimal forbidden subgraphs of a hereditary property in terms of its minimal forbidden induced-subgraphs, and <i>vice versa</i>; · extensions of Mihók's construction of uniquely colourable graphs, and Scheinerman's characterisations of compositivity, to disjoint compositive properties; · an induced-hereditary property has at least two factorisations into arbitrary irreducible properties, with an explicitly described set of exceptions; · if <i>G</i> is a generating set for <i>A</i> &#959; <i>B</i>, where <i>A</i> and <i>B</i> are indiscompositive, then we can extract generating sets for <i>A</i> and <i>B</i> using a <i>greedy algorithm</i>.

The study and recognition of graph families (or graph properties) is an essential part of combinatorics. Graph colouring is another fundamental concept of graph theory that can be looked at, in large part, as the recognition of a family of graphs that are colourable according to certain rules. In this thesis, we study additive induced-hereditary families, and some generalisations, from a colouring perspective. Our main results are: · Additive induced-hereditary families are uniquely factorisable into irreducible families. · If <i>P</i> and <i>Q</i> are additive induced-hereditary graph families, then (<i>P</i>,<i>Q</i>)-COLOURING is NP-hard, with the exception of GRAPH 2-COLOURING. Moreover, with the same exception, (<i>P</i>,<i>Q</i>)-COLOURING is NP-complete iff <i>P</i>- and <i>Q</i>-RECOGNITION are both in NP. This proves a 1997 conjecture of Kratochvíl and Schiermeyer. We also provide generalisations to somewhat larger families. Other results that we prove include: · a characterisation of the minimal forbidden subgraphs of a hereditary property in terms of its minimal forbidden induced-subgraphs, and <i>vice versa</i>; · extensions of Mihók's construction of uniquely colourable graphs, and Scheinerman's characterisations of compositivity, to disjoint compositive properties; · an induced-hereditary property has at least two factorisations into arbitrary irreducible properties, with an explicitly described set of exceptions; · if <i>G</i> is a generating set for <i>A</i> &#959; <i>B</i>, where <i>A</i> and <i>B</i> are indiscompositive, then we can extract generating sets for <i>A</i> and <i>B</i> using a <i>greedy algorithm</i>.