TITLE: Is there a name for this equivalence relation?
QUESTION [7 upvotes]: Let $M$ be an arbitrary set and let $\mathscr{F}$ be a family of subsets of $M$. Is there a known name for the following equivalence relation or its corresponding partition?
$\sim_{M,\mathscr{F}}\,=\bigl\{(x,y)\in M\times M\bigm|\forall A\in\mathscr{F}\,(x\in A\leftrightarrow y\in A)\bigr\}$.

REPLY [7 votes]: $\mathscr F$-indistinguishability.
In analogy with Topological indistinguishability.

REPLY [5 votes]: The elements of this partition are precisely the atoms of the complete Boolean algebra generated by the family.