This article discusses several forms of Ulam stability nonlinear fractional delay differential equations. Our investigation is based on a generalised Gronwall’s inequality and Picard operator theory. Implementations are provided to demonstrate the results obtained for finite intervals.

This article aims to mark out new conditions for oscillation of the even-order Emden–Fowler neutral delay differential equations with term ?1???[?r?1?]?+?3???[???]=0. The obtained results extend, and simplify known in literature. are illustrated examples.