What causes the conflict between Ged and Jasper in chapter 4 of A Wizard of Earthsea?
I think you have to be careful to distinguish between the apparent "spark" that triggered off Ged's decision to prove himself to Jasper by raising the dead and then the underlying feelings of pride and mastery that have been simmering in Ged long before he actually met Jasper at Roke. Certainly, if you are focussing only on the former, this conflict emerges as a response to one of Jasper's taunts whilst the apprentices at Roke are celebrating the Long Dance. Jasper says:
"I want the company of my equals."
This clearly indicates the superiority that Jasper feels he has over Ged. In response, Ged is driven to challenge Jasper by an act of power that will show his superiority to him. But note how this is merely a cover for a far greater failing within the character of Ged - his pride. Even Jasper recognises that this conflict has been coming long before, as he says to Ged:
"Envy eats you like a work in an apple."
The pride of Ged, the all-consuming desire to prove himself, has been established long before the events of Chapter 4, and we as readers are left to think that even if Jasper hadn't met Ged, someone else or another event would have triggered off something similar. The conflict then says more about Ged and his failings than it does about Jasper.