1) Like good kids 
Mathematicians (and those in related sciences) very frequently speak of whether a mathematical object—a function, a set, a space of one sort or another—is `well-behaved`. The term has no fixed formal definition, and is dependent on context, mathematical interests, fashion, and taste. To ensure that an object is `well-behaved` mathematician...
[adj] - (usually of children) someone who behaves in a manner that the speaker believes is correct
well behaved adjective (usually of children) someone who behaves in a manner that the speaker believes is correct; `a well-behaved child`
A condition that exhibits expected properties.