It feels like "relatively little" to many authors means "a complete set of undergrad math courses from a fairly math-heavy major" (which could be something like calculus including vectors, differential equations, linear algebra, real analysis, and maybe abstract algebra and discrete math). Maybe we need another term for "OK with logic, proofs, and calculations and doesn't mind learning notation, but hasn't had a lot of university-level courses, or in any event doesn't remember them".