Weak solutions for implicit Pettis--Hadamard fractional differential equations with retarded and advanced arguments

  • Sa\"{\i}d Abbas
  • Mouffak Benchohra
  • Jamal Eddine Lazreg
  • Gaston N'Gu\'er\'ekata


In this paper, we present some results concerning the existence of weak solutions for some functional implicit differential equations of Hadamard fractional derivative involving both retarded and advanced arguments. The main results are proved by applying M\"onch's fixed point theorem associated with the technique of measure of weak noncompactness.