Lectures on Partial Differential Equations Quotes

“Instead of the principle of maximal generality that is usual in mathematical books the author has attempted to adhere to the principle of minimal generality, according to which every idea should first be clearly understood in the simplest situation;
only then can the method developed be extended to more complicated cases.
Although it is usually simpler to prove a general fact than to prove numerous special cases of it, for a student the content of a mathematical theory is never larger than the set of examples that are thoroughly understood.”
― Vladimir I. Arnold, Lectures on Partial Differential Equations