> Maybe in cases like this, ode2 should return a noun form?
I like the idea of a noun form, but what noun form would you use?
Even for scalar _solve_, we don't have an appropriate nounform meaning
"the set of x such that ...", e.g.
solve(x=cos(x),x) => {x | x=cos(x)}
What would be the equivalent for a DE?
I suppose it could be 'ode(...), but that seems rather ugly as a
mathematical object, unlike 'limit, 'integrate, 'diff, etc.