Research Article On Some Existence and Uniqueness Results for a Class of Equations of Order 0<≤1 on Arbitrary Time Scales Abdourazek Souahi, 1 Assia Guezane-Lakoud, 2 and Rabah Khaldi 2 1 Laboratory of Applied Mathematics and Modeling, University of 8 May 1945 Guelma, P.O. Box 401, 24000 Guelma, Algeria 2 Laboratory of Advanced Materials, University of Badji Mokhtar-Annaba, P.O. Box 12, 23000 Annaba, Algeria Correspondence should be addressed to Abdourazek Souahi; arsouahi@yahoo.fr Received 21 April 2016; Accepted 9 June 2016 Academic Editor: Patricia J. Y. Wong Copyright © 2016 Abdourazek Souahi et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Tis paper investigates the existence and uniqueness of solution for a class of nonlinear fractional diferential equations of fractional order 0<≤1 in arbitrary time scales. Te results are established using extensions of Krasnoselskii-Krein, Rogers, and Kooi conditions. 1. Introduction Tis work concerns the investigation of sufcient conditions for the existence and uniqueness of the solution of the fol- lowing initial value problem with fractional derivative up to the frst order on arbitrary time scales: T ()=(,()), ∈[ 0 , 0 +] T ,0<≤1, T 1− ( 0 )=0, (1) where T is the (lef) Riemann-Liouville fractional deriva- tive of order on time scales T , T is the Riemann-Liouville fractional integral on time scales, and [ 0 , 0 +] T is an interval on T . We assume that is a right-dense continuous function. Te theory of time scales calculus allows us to study the dynamic equations, which include both diference and diferential equations, both of which are very important in implementing applications; for further information about the theoretical and potential applications of the theory of time scales, we refer the reader to [1–8] and the survey [9]. Te quantitative behaviour of solutions to ordinary dif- ferential equations on time scales is currently undergoing active investigations. Many authors studied the existence and the uniqueness of the solutions of initial and boundary diferential equations; see [8, 10–20] and the references cited therein. In the papers [21–25], several authors were interested by the existence and uniqueness of the frst-order diferential equations on time scales with initial or boundary conditions using diverse techniques and conditions. On the other hand, some existence results for the fractional order diferential equations were obtained in [10]. Our ideas arise from the papers [26–34], especially [30, 31], where the authors used Nagumo and Krasnoselskii-Krein conditions on the nonlinear term , without satisfying Lip- schitz assumption. Motivated greatly by the above works, under appropriate time scales versions of the Krasnoselskii- Krein conditions, we obtain the uniqueness and existence of solution for the following two classes of diferential equations, namely, the frst-order ODE Δ ()=(,()), ∈[ 0 , 0 +] T , ( 0 )=0, (2) and the fractional order FDE: T ()=(,()), ∈[ 0 , 0 +] T ,0<≤1, T 1− ( 0 )=0. (3) Hindawi Publishing Corporation International Journal of Differential Equations Volume 2016, Article ID 7327319, 8 pages http://dx.doi.org/10.1155/2016/7327319