http://dspace.univ-tiaret.dz:80/handle/123456789/85 2026-04-07T14:58:18Z http://dspace.univ-tiaret.dz:80/handle/123456789/16951 Titre: Bullen and Milne inequalities involving h-convex functions Auteur(s): DJEBLI, Bochra; Yazid, Fatima Zohra Racha 2025-06-10T00:00:00Z http://dspace.univ-tiaret.dz:80/handle/123456789/16918 Titre: A Study of Some Fuzzy Fractional Differential Equations Auteur(s): Abubakar, Atiku Uba Résumé: In this dissertation, we present the study of some fuzzy fractional differential equations, in the first one, we prove that fuzzy fractional differential equation is equivalent to the fuzzy integral equation and then using this equivalence existence and uniqueness result is establish. Fuzzy derivative is consider in the GoetschelVoxman sense and fractional derivative is consider in the Riemann Liouville sense. Also we give some applications of the main result. Secondly the work is concerned with the existence and uniqueness of solutions of fuzzy fractional differential equations using fixed point theory. We provide some results answering when we can expect a solution of the problem. Thirdly we primarily focused on the existence and uniqueness of the initial value problem for fractional order fuzzy ordinary differential equations in a fuzzy metric space. 2025-01-01T00:00:00Z http://dspace.univ-tiaret.dz:80/handle/123456789/16914 Titre: Dynamiques de Compétition dans les Chémostats : Modélisation Mathématique des Plasmides Auteur(s): BELABID, Chaia Résumé: Ce mémoire vise à étudier des modèles mathématiques décrivant la dynamique de compétition entre des souches bactériennes porteuses et non porteuses de plasmide dans un chémostat. Trois cas sont analysés : égalité des taux de dilution, inégalité entre les souches, et introduction d’un inhibiteur externe. L’analyse repose sur l’étude des équilibres, la matrice Jacobienne et les critères de stabilité, avec représentation de diagrammes opératoires. Les ré- sultats montrent la coexistence possible, l’exclusion compétitive ou des comportements périodiques selon les paramètres. Description: This thesis aims to study mathematical models describing the competitive dynamics between plasmid-bearing and plasmidfree bacterial strains in a chemostat. Three scenarios are analyzed : equal dilution rates, unequal rates between strains, and the effect of an external inhibitor. The analysis is based on equilibrium study, Jacobian matrix, and stability criteria, supported by operational diagrams. The results reveal conditions leading to coexistence, competitive exclusion, or periodic behaviors depending on system parameters. 2025-01-01T00:00:00Z http://dspace.univ-tiaret.dz:80/handle/123456789/16911 Titre: Etude de certains problèmes d'évolution avec conditions non locales Auteur(s): HAMMADI, Nadia; Khelifi, Rouba 2025-01-01T00:00:00Z