Always present; always there
An athlete who is present in every contest.
Indefinitely continuous.
Of data or a data structure: not transient or temporary, but remaining in existence after the termination of the program that creates it.
Describing a fractal process that has a positive Brown function
Lasting past maturity without falling off.
non-transient.
Obstinately refusing to give up or let go.
Insistently repetitive.