My field is applied mathematics, and I regularly hire short term undergraduate students as research assistants to work on various projects.
Most students, for a variety of reasons, cannot make any substantial contributions, yet most of them end up making a tiny but nonzero amount of contribution. Since the main subject is mathematics, it is usually difficult to quantify/describe the contributions. E.g., a student notice some patterns in some numerical simulation, which, years later, leads to a theorem. Or a student run some numerical computations, and eliminated some hypothesis.
What is the standard way of giving credit to such student making epsilon amount of contributions?