The first chapter comprises a survey of valuations on totally ordered structures, developing notation and properties. A contraction map is induced by the exponential map on the value group $G$ of an ordered exponential field $K$ with respect to the natural valuation $v_{G}$. By studying the algebraic properties of Abelian groups with contractions, the theory of these groups is shown to be model complete, complete, decidable and to admit elimination of quantifiers. Hardy fields provide an example of non-archimedean exponential fields and of differential fields and therefore, they play a very important role in our research.<p>In accordance with Rosenlicht we define asymptotic couples and then give a short exposition of some basic facts about asymptotic couples. The theory $T_{P}$ of closed asymptotic triples, as defined in Section 2.4, is shown to be complete, decidable and to have elimination of quantifiers. This theory, as well as the theory $T$ of closed $H$-asymptotic couples do not have the independence property. The main result of the second chapter is that there is a formal connection between asymptotic couples of $H$-type and contraction groups.<p>A given valuation of a differential field of characteristic zero is a differential valuation if an analogue of l'Hospital's rule holds. We present in the third chapter, a survey of the most important properties of a differential valuation. The theorem of M. Rosenlicht regarding the construction of a differential field with given value group is given with a detailed proof. There exists a Hardy field, whose value group is a given asymptotic couple of Hardy type, of finite rank. We also investigate the problem of asymptotic integration.

The first chapter comprises a survey of valuations on totally ordered structures, developing notation and properties. A contraction map is induced by the exponential map on the value group $G$ of an ordered exponential field $K$ with respect to the natural valuation $v_{G}$. By studying the algebraic properties of Abelian groups with contractions, the theory of these groups is shown to be model complete, complete, decidable and to admit elimination of quantifiers. Hardy fields provide an example of non-archimedean exponential fields and of differential fields and therefore, they play a very important role in our research.<p>In accordance with Rosenlicht we define asymptotic couples and then give a short exposition of some basic facts about asymptotic couples. The theory $T_{P}$ of closed asymptotic triples, as defined in Section 2.4, is shown to be complete, decidable and to have elimination of quantifiers. This theory, as well as the theory $T$ of closed $H$-asymptotic couples do not have the independence property. The main result of the second chapter is that there is a formal connection between asymptotic couples of $H$-type and contraction groups.<p>A given valuation of a differential field of characteristic zero is a differential valuation if an analogue of l'Hospital's rule holds. We present in the third chapter, a survey of the most important properties of a differential valuation. The theorem of M. Rosenlicht regarding the construction of a differential field with given value group is given with a detailed proof. There exists a Hardy field, whose value group is a given asymptotic couple of Hardy type, of finite rank. We also investigate the problem of asymptotic integration.

Cette thèse a pour objet les ordres, les valuations et les C-relations sur les groupes, ainsi que les corps différentiels valués tels qu’étudiés par Rosenlicht. Elle accomplit trois objectifs principaux. Le premier est d’introduire et d’étudier une notion de quasi-ordre sur les groupes qui a pour but de réunir les ordres et les valuations dans un même cadre. Nous donnons un théorème de structure des groupes munis d’un tel quasi-ordre, ce qui nous permet ensuite de donner un “théorème de plongement de Hahn” pour ces groupes. Le second objectif de cette thèse est de décrire les C-groupes à l’aide des quasi-ordres. Nous donnons un théorème de structure pour les C-groupes, qui énonce que tout C-groupe est un “mélange” de groupes ordonnés et de groupes valués. Nous utilisons ensuite ce résultat pour caractériser les groupes C-minimaux à l’intérieur de la classe des C-groupes. Le troisième objectif de cette thèse est d’introduire et d’étudier une notion de rang différentiel d’un corps différentiel valué. Nous définissons cette notion par analogie avec les notions de rang exponentiel d’un corps exponentiel et de rang de différence d’un corps aux différences. Nous montrons que cette notion de rang n’est pas tout à fait satisfaisante, et introduisons donc une meilleure notion de rang appelée le rang différentiel déployé. Nous donnons ensuite une méthode pour définir une dérivation “de type Hardy” sur un corps de séries formelles généralisées, ce qui nous permet de construire des corps différentiels valués dont le rang différentiel et le rang différentiel déployé ont été arbitrairement choisis. / This thesis deals with orders, valuations and C-relations on groups, and with differential-valued fields à la Rosenlicht. It achieves three main objectives. The first one is to introduce and study a notion of quasi-order on groups meant to encompass orders and valuations in a common framework. We give a structure theorem for groups endowed with such a quasi-order, which then allows us to give a “Hahn’s embedding theorem” for these groups. The second objective of this thesis is to describe C-groups via quasi-orders. We give a structure theorem for C-groups, which basically states that any C-group is a “mix” of ordered groups and valued groups. We then use this result to characterize C-minimal groups inside the class of C-groups. The third objective of this thesis is to introduce and study a notion of differential rank for differential-valued fields. We define this notion by analogy with the exponential rank of an exponential field and with the difference rank of a difference field. We show that this notion of rank is not quite satisfactory, so we introduce a better notion of rank called the unfolded differential rank. We then give a method to define “Hardy-type” derivations on fields of generalized power series, which allows us to build differential-valued fields of arbitrary given differential rank and unfolded differential rank.