In this thesis we look at hom-associative algebras (which turn out to be exactly the G1-hom-associative algebras), by, in two and three dimensions, trying to find the structure constants for which an algebra becomes hom-associative when the homomorphism 𝛼 is defined as different matrix units. These algebras are also hom-Lie admissible (or G6-hom-associative, which turn out to be the same thing) with a commutator, so we also find the commutator for each of these hom-Lie admissible algebras. We end up finding every hom-associative and hom-Lie algebra for 𝛼 defined as each 2×2 matrix unit in two dimensions, each 3×3 matrix unit in three dimensions when the problem is mapped to one dimension, for three 3×3 matrix units in three dimensions when the problem is mapped to two dimensions (but with the commutators not having been calculated), and only a few hom-associative algebras and hom-Lie algebras for one 3×3 matrix unit in the full three dimensions. We also compare the results for the different values of 𝛼, and find that in 𝑛 dimensions it is possible to find the values of the structure constants for all 𝑛2 different 𝛼:s simply by finding all of the solutions for 𝑛 different 𝛼:s (chosen in a specific way) and then permutating all of the indices.

La thèse comporte six chapitres. Dans le premier chapitre, on rappelle les bases de la théorie et on étudie la structure des algèbres Hom-associatives ainsi que les différentes constructions comme la composition avec des endomorphismes qui nous permet de construire de nouveaux objets et d’établir certaines nouvelles propriétés. Parmi les résultats originaux, on peut signaler l’étude des algèbres Hom-associatives simples ainsi que leurs constructions. On a montré que toutes les algèbres Hom-associatives multiplicatives simples s’obtiennent par composition d’algèbres simples et d’automorphismes. Dans le deuxième chapitre, on commence par étudier les propriétés des changements de base dans ces structures algébriques. On a calculé la base de Gröbner de l’idéal engendrant la variété algébrique des algèbres Hom-associatives de dimension 2 où la multiplication µ et l’application linéaire α sont identifiées à leurs constantes de structure relativement à une base donnée. La classification, à isomorphisme près, des algèbres Hom-associatives unitaires et non unitaires est établie en dimension 2 et 3. On a aussi décrit les algèbres de type associatif en se basant sur le théorème de twist de Yau. Dans le troisième chapitre, on étudie certaines propriétés et invariants comme les dérivations, αk-dérivations où k est un entier positif. Dans le quatrième chapitre, on établit la cohomologie de ces algèbres. On a pu lister les algèbres rigides grâce à leur classe de cohomologie puis on s'est 'intéressé aux déformations infinitésimales et dégénérations. D’une part, la cohomologie et déformation de ces algèbres nous a permis d’identifier les algèbres rigides dont le deuxième groupe de cohomologie est nulle, et d’autre part de caractérisation de composante irréductible. Dans le cinquième chapitre, on s’intéresse aux structures Rota-Baxter de poids λ ϵK de ces algèbres. Enfin, dans le dernier chapitre, on a travaillé sur les structures Hom-bialgèbres et leurs invariants. / The purpose of this thesis is to study the structure of Hom-associative algebras and provide classifications. Among the results obtained in this thesis, we provide 2-dimensional and 3-dimensional Hom-associative algebras and give a characterization of multiplicative simple Hom-associative algebras. Moreover we compute some invariants and discuss irreducible components of the corresponding algebraic varieties. The thesis is organized as follows. In the first chapter we give the basics about Hom-associative algebras and provide some new properties. Moreover, we discuss unital Hom-associative algebras. Chapter 2 deals with simple multiplicative Hom-associative algebras. We present one of the main results of this paper, that is a characterization of simple multiplicative Hom-associative algebras. Indeed, we show that they are all obtained by twistings of simple associative algebras. Chapter 3 is dedicated to describe algebraic varieties of Hom-associative algebras and provide classifications, up to isomorphism, of 2-dimensional and 3-dimensional Hom-associative algebras. In chapter 4, we compute their derivations and twisted derivations, whereas in chapter 5, we compute their Hom-Type Hochschild cohomology. In the last section of this chapter, we consider the geometric classification problem using one-parameter formel deformations, and describe the irreducible components. In chapter 6, we compute Rota-Baxter structures of weight k of Hom-associative algebras appearing in our classification. In chapter 7, We work out Hom-bialgebras structures as well as their invariants. Properties and classifications, as well as the calculation of certain invariants such as the first and second cohomology groups, were studied.

In this thesis, we consider hom-associative algebras, which is an algebra with multiplication that is not necessarily commutative nor associative, but obeys a twisted version of associativity by a linear homomorphism. We will give some conditions for associativity, which helps us determine commuting elements. Under other conditions, such as different types of unitality conditions, we can also state some results regarding commuting elements in the general, non-associative case.

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