The objects studied in this thesis are families of cycles on schemes. A space — the Chow variety — parameterizing effective equidimensional cycles was constructed by Chow and van der Waerden in the first half of the twentieth century. Even though cycles are simple objects, the Chow variety is a rather intractable object. In particular, a good functorial description of this space is missing. Consequently, descriptions of the corresponding families and the infinitesimal structure are incomplete. Moreover, the Chow variety is not intrinsic but has the unpleasant property that it depends on a given projective embedding. A main objective of this thesis is to construct a closely related space which has a good functorial description. This is partly accomplished in the last paper. The first three papers are concerned with families of zero-cycles. In the first paper, a functor parameterizing zero-cycles is defined and it is shown that this functor is represented by a scheme — the scheme of divided powers. This scheme is closely related to the symmetric product. In fact, the scheme of divided powers and the symmetric product coincide in many situations. In the second paper, several aspects of the scheme of divided powers are discussed. In particular, a universal family is constructed. A different description of the families as multi-morphisms is also given. Finally, the set of k-points of the scheme of divided powers is described. Somewhat surprisingly, cycles with certain rational coefficients are included in this description in positive characteristic. The third paper explains the relation between the Hilbert scheme, the Chow scheme, the symmetric product and the scheme of divided powers. It is shown that the last three schemes coincide as topological spaces and that all four schemes are isomorphic outside the degeneracy locus. The last paper gives a definition of families of cycles of arbitrary dimension and a corresponding Chow functor. In characteristic zero, this functor agrees with the functors of Barlet, Guerra, Kollár and Suslin-Voevodsky when these are defined. There is also a monomorphism from Angéniol's functor to the Chow functor which is an isomorphism in many instances. It is also confirmed that the morphism from the Hilbert functor to the Chow functor is an isomorphism over the locus parameterizing normal subschemes and a local immersion over the locus parameterizing reduced subschemes — at least in characteristic zero. / QC 20100908

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On étudie la correspondance de Howe entre la catégorie de représentations complexes de G et celle de G’, pour des paires duales irréductibles (G,G’) définis sur des corps finis de caractéristique impaire. On établit la compatibilité entre la correspondance de Howe et les séries arbitraires de Harish-Chandra. On démontre comment obtenir des sous-représentations extrémales (i.e. minimales et maximales) de l’image d’une représentation irréductible unipotente de G. Finalement, on démontre comment l’étude de la correspondance de Howe entre séries d’Harish-Chandra arbitraires peut être ramenée à l’étude des séries unipotentes, et on utilise ceci pour étendre nos résultats sur les représentations extrémales aux représentations irréductibles arbitraires (i.e. pas forcément unipotentes) de G. / We study the Howe correspondence between the category of complex representations of G and that of G’, for irreducible dual pairs (G,G’) over finite fields of odd characteristic. We establish the compatibility between the Howe correspondence and arbitrary Harish-Chandra series. We define and prove the existence of extremal (i.e. minimal and maximal) irreducible sub-representations from the image of irreducible unipotent representations of G. Finally, we prove how the study of the Howe correspondence between arbitrary Harish-Chandra series can be brought to the study of unipotent series, and use this to extend our results on extremal representations to arbitrary (i.e. not necessarily unipotent) irreducible representations of G.

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The topic of the diploma thesis is symplectic spinor geometry. Its re- search was started by D. Shale, B. Kostant and K. Habermann. We focus our attention to one of the so called symplectic twistor operators introduced by S. Kr'ysl. We investigate the action of this operator on real even dimensio- nal vector spaces considered as symplectic manifold, its invariance properties and regularity. We describe a part of the kernel of the symplectic twistor operator when acting on symplectic spinors on R2. The kernel forms a repre- sentation of the so called metaplectic group (double cover of the symplectic group). 1

Cette thèse s’intéresse à la conception de la résistance dans les travaux de Simone Weil (1909-1943) et de Michel Foucault (1926-1984). Nous y étudions plus précisément les « techniques de soi » que constituent l’ascèse et la mystique. Partant du postulat que les dispositifs de pouvoir actuels reposent aussi bien sur l’individualisme que la dépolitisation, l’objectif est de mettre en avant des « contre-conduites » susceptibles de favoriser voire de recréer une certaine forme d’existence en commun. Nous soutenons ainsi l’idée que l’ascèse et la mystique peuvent – à condition d’être repensées – représenter de véritables armes dans les luttes transversales et continues qui caractérisent notre époque, tout en offrant des modèles d’action opposés à ceux mis en avant par le système capitaliste. À travers la lecture, l’écriture, l’amitié, l’amour, et plus largement une forme d’attention redoublée envers les autres, les techniques de soi conceptualisées par les auteurs peuvent être définies comme un refus préliminaire qui doit mener à des changements structurels plus profonds. En retour, les formes de vie résultant de la mise en place de ces techniques doivent renforcer cette « anti-discipline ». Par-là, il est possible de décrire la mystique weilienne et l’ascèse foucaldienne comme une révolution permanente, c’est-à-dire un éthos révolutionnaire qui offre une alternative à l’échec du « Grand Soir ». Il s’agit en somme d’analyser les conditions de déconstruction et/ou de recréation d’un « soi » qui représente actuellement le pivot de l’oppression sociale. Le travail peut donc aussi bien se lire comme une critique de l’injonction à être soi-même que comme un appel à devenir autre chose que ce que nous sommes. D’un point de vue plus général, l’objectif est également de mettre en dialogue deux auteurs rarement rapprochés dans la philosophie contemporaine, ainsi que d’effectuer un certain nombre de parallèles avec les traditions de pensée anarchistes et postcoloniales pour montrer tout ce que celles-ci ont en commun. / Abstract : This thesis studies the notion of resistance in the works of Simone Weil (1909-1943) and Michel Foucault (1926-1984). It deals more precisely with two technologies of the self, ascetism and mystic. As individualism and depoliticization seem to characterize “late capitalist” societies, our goal is to present some “counter-conducts” that could foster and even re-create common lifeforms. Under certain conditions, we support the idea that these technologies can be of great support in the permanent and transversal struggles of our times, while offering a praxeological model that doesn’t match the capitalism generic set of values. Through skills such as reading, writing, love or friendship, and a reinforced attention to the world, the technologies of the self depicted by Weil and Foucault could be described as a first act of resistance that can lead to deeper and greater structural changes. In a dialectical way, the structures resulting of these practices also must favorize the emergence of an “anti-discipline”. Regarding to these elements, Weil’s mystic and Foucault’s asceticism look like attempts to put permanent revolution in practice and propose an interesting alternative to the communist model. The goal of this thesis is therefore to analyze some ways of deconstructing and/or recreating a “self” that currently represents a coercive and oppressive force. More generally, it aims to create a discussion between two thinkers that are rarely studied together, and to draw some parallels with anarchist and post-colonial thoughts to show how much all these movements share.

Ce mémoire s’intéresse à la centralité politique du travail à travers une lecture croisée des pensées de la philosophe française Simone Weil (1909-1943) et de l’anthropologue états-unien David Graeber (1961-2020). Il se penche sur le potentiel qu’a le travail de nous former à l’activité politique en développant notre sensibilité au monde qui nous entoure, ainsi qu’à autrui. Nous interrogeons d’abord la forme actuelle que prend le travail. Nous creusons pour ce faire le phénomène de bullshitization de l’économie, décrite par Graeber comme la hausse de la part du temps au travail accordé à l’accomplissement de tâches superflues, de même qu’à l’augmentation générale des emplois inutiles, dits bullshit jobs. Phénomène lié à la bureaucratisation néolibérale croissante de tous les secteurs de la vie, les bullshit jobs impliquent aliénation, ennui et maux physiques liés au stress. Son occupant·e, par la conscience de l’inutilité sociale de son travail, se voit privé·e de participer à la collectivité de manière significative. Iel est, pour emprunter un langage weilien, déraciné·e. Via les travaux de Weil sur le travail d’usine, nous affirmons une certaine continuité entre les formes d’aliénation au travail décrites par Weil et Graeber. Il y a, dans le travail à la chaine des années 1930, dans les bullshit jobs et dans les emplois bullshitizés, une dissociation entre les gestes et la pensée. Dans son expérience en usine, Weil observe la perte de la capacité à exercer son esprit au travail comme un arrachement à la condition humaine. De cette dissociation découle donc une douleur psychologique et sociale considérable — dite « déracinement » —, ainsi que des formes d’hostilité politique. Nous nous penchons finalement sur le potentiel politique d’un travail digne. Pour Simone Weil, la centralité politique du travail découle de sa propension à cultiver la capacité d’attention. Plus qu’une simple capacité cognitive, l’attention est à la fois ce qui permet la liberté individuelle (être capable d’orienter par soi-même son attention) et ce qui favorise le rapport éthique aux autres. La pratique de l’attention au travail permet en ce sens de développer la réceptivité envers autrui, l’un des fondements de la qualité des rapports démocratiques. Pour David Graeber, le travail, sous certaines conditions, se révèle comme lieu de déploiement de l’imagination. Cette dernière permet la nouveauté politique, car elle tend à décloisonner l’imaginaire de cellui qui l’exerce. Chez Weil comme chez Graeber, le travail peut engendrer des relations sociales émancipatrices qui échappent aux rapports de pouvoir oppressifs. / This master’s thesis examines the political centrality of work through a comparative reading of the works of French philosopher Simone Weil (1909–1943), and American anthropologist David Graeber (1961–2020). It focuses on the potential of work as an activity prone to the development of a form of sensitivity to the world, and to other people. We first consider the present experience of work through Graeber’s concept of bullshitization. The bullshitization of the economy refers to the increase of time and energy at work dedicated to needless tasks, as well as to the increase of useless jobs, which Graeber calls “bullshit jobs”. Inseparable from the neoliberal bureaucratization of all branches of life, bullshit jobs lead to alienation, boredom and physical pains related to stress. Moreover, the bullshit worker is kept from having a significant impact on the community they inhabit; they are, in the words of Simone Weil, uprooted (déraciné·e). Through a reading of the Weil’s writings on factory work in 1930s′ France, we establish a continuity between the forms of suffering at work theorized by Graeber and Weil: at the factory, in bullshit jobs and in jobs that have been bullshitized, there is a disconnect between thought and action. During her experience as a factory worker, Weil describes the loss of thinking at work as a stripping of the human condition. From this separation derives not only psychological and social suffering (uprootedness [déracinement]), but also forms of political hostility. We finally explore the political potential of dignified work. Weil derives the political centrality of work from its propension to encourage the practice of attention. More than a cognitive ability, attention is a condition for individual freedom and fosters ethical relationships to others. Attention thus enables openness and receptiveness to others—one of the foundations of a healthy democratic life. For Graeber, work can nurture imagination, which in turn enables the imagining of new political practices. For Simone Weil and David Graeber, dignified work can bring on new and emancipatory social relations, free from oppressive power dynamics.

This bachelor thesis engages in a quest to understand the concepts of necessity and grace in Simone Weils thinking. The question in play, in which many more questions lie hidden, reads as follows: How does Weil understand the operations of grace in relation to the ”blind necessity” of the natural world, and what are the philosophical implications of this concept of grace? What are, for instance, given her understanding of the world as God’s creation, the metaphysical grounds for a basic human activitiy such as thinking or reflexion? A reading of Simone Weils works on necessity, grace, affliction and attention is contrasted with her thoughts on science, method and truth. The concept of necessity is compared to the one of Spinoza, especially on the subject of how the good or the just relates to the true and the necessary: it shows there are interesting similarities and illuminating differences between the two philosophers’ lines of thought. Here, the concept of attention becomes central to the image: the idea of a cultivated mode of reception of the world and of the Other. Attention is analogously understood as a method of prayer and a cultivated ethical attitude towards other human beings – and an ideal scientific state of mind. In the final chapter of the analytic part of the composition, Weils concept of grace is investigated in regard to concepts of thinking and understanding. Here, Leibniz idea of the divine world and the divine mind plays a concise but important role on the matter of a tentative metaphysical grounding of thinking as such – how this can be thought and how it reflects and deepens Simone Weils metaphysics, especially her understanding of the highest states of insight into the nature of the world as partly a work of divine grace. In the last chapter Walter Benjamins vision of the coming philosophy as a consolidation between Immanuel Kants transcendental philosophy and religious experience – and religious thought – show the way for further investigation into the field, a field that the thesis has outlined at the same time as it has attempted to answer some specific questions that seems to be the most urgent ones.

On est consciemment ou inconsciemment influencé par le scientisme et le positivisme logique. Nous posons donc une question : Peut-on parler de Dieu aujourd’hui ? Pour répondre à cette question, nous choisissons deux philosophes : Wittgenstein et Simone Weil. Selon Wittgenstein, « sur ce dont on ne peut parler, il faut garder le silence ». Ce qu’il veut dire par là, ce n’est pas que Dieu n’existe pas ou que Dieu n’est pas intelligible comme le disent le scientisme et le positivisme logique. Ce qu’il veut dire par là, c’est que Dieu existe effectivement, mais que l’on ne peut parler de lui en raison de la limite de notre langage. Or, la faute de Wittgenstein consiste à détourner les yeux de l’intelligibilité religieuse ou métaphysique. En ce qui concerne Simone Weil, elle parle de Dieu dans ses écrits et ses lettres. Qu’est-ce qui lui permet de parler de Dieu ? C’est le premier intérêt de ce projet. Et le deuxième intérêt consiste à déterminer l’expérience mystique de Simone Weil, car l’utilisation du mot « mystique » dans les études sur elle est assez arbitraire. Le troisième intérêt est de mettre en relief la relation entre la non-lecture et l’intuition chez elle. Enfin, le cinquième intérêt est de traiter la relation entre le bouddhisme zen et la pensée de Simone Weil. A travers nos études sur le concept d’intuition chez Simone Weil, nous proposerons une autre vision du monde que le scientisme et le positivisme logique. / We are consciously or unconsciously influenced by scientism and logical positivism. So we asked a question: Can we speak of God today? To answer the question, we focus on two philosophers, Wittgenstein and Simone Weil. According to Wittgenstein, “Whereof one cannot speak, thereof one must be silent.” What he means by that is not that God doesn’t exist or that God is not intelligible as say scientism and logical positivism. What he means by that is that God does exist, but we can’t talk about him because of the limits of our language. But the lack of Wittgenstein is to look away from religious or metaphysical intelligibility. As for Simone Weil, she speaks of God in her writings and letters. What allows her to speak of God? This is our first point of interest. And our second point of interest is to define the mystical experience of Simone Weil, because the use of the word “mystical” in studies of Weil is rather arbitrary. Our third point of interest is to highlight the relationship between “non-reading” and intuition in Simone Weil. Our fourth point of interest is to explore the relationship between Zen Buddhism and the thought of Simone Weil. Through studying them, we will answer this question and, through Weil’s concept of intuition, we propose a worldview that is different from scientism and from logical positivism.

The overall objective of the thesis is to investigate needs and incentives of all income/wealth groups in order to explore ways and means to remedy the excessive economic inequality. A closer examination of individual decisions across richer and poorer households allows us to recognize conflicts of wants, needs and values and subsequently to draw recommendations for future policies. The first chapter examines households' preferences over the redistribution of wealth resources. The preferences of voting households are restricted by agents' present and future resource constraints. The wealth resources vary over the business cycle, which affects the grounds for speculations of voting households. We augment the standard Real-Business-Cycle (RBC) model by the majority voting on lump-sum redistribution employing a balanced government budget. Our findings indicate that for the usual elasticity of labor supply both transfers' level and share of output are procyclical, with the procyclicality increasing in the discrepancy between richer and poorer households. In the second chapter we analytically demonstrate that all economic agents face subsistence costs that hinder economic and financial decisions of the poor. We find that the standard two-asset portfolio-selection model with a time-invariant subsistence component in the common-across agents Stone-Geary utility function is capable of explaining qualitatively and quantitatively three empirical regularities: (i) increasing saving rates in wealth, (ii) rising risky portfolio shares with wealth, (iii) more volatile consumption growth of the richer. On the contrary, "keeping-up-with-the-Joneses" utility with a time-varying weighted mean consumption produces identical saving rates and portfolio asset shares across richer and poorer agents, failing to match the micro data. Finally, in the third chapter we use Epstein-Zin-Weil recursive preferences altered to include subsistence costs, as this form of utility function enables trade-off between stability and safety. We pursue an analytical investigation of a more complex multi-asset portfolio-choice model with perfectly insurable labor risk and no liquidity constraints and find further support of the data evidence. If households' total resources are anticipated to increase over time, poorer agents can afford to gradually escape subsistence concerns by choosing lower saving rates and accepting only minor portfolio risks as their consumption hovers close to the subsistence needs. The calibration part of the model economy shows that analytical results can quantitatively reconcile the data, too.