Proper Filter

Some articles on filter, proper:

Filter (mathematics) - Filter On A Set
... A special case of a filter is a filter defined on a set ... Define a filter F on S as a subset of P(S) with the following properties S is in F ... (F is proper) If A and B are in F, then so is their intersection ...

Famous quotes containing the word proper:

    The reputation of generosity is to be purchased pretty cheap; it does not depend so much upon a man’s general expense, as it does upon his giving handsomely where it is proper to give at all. A man, for instance, who should give a servant four shillings, would pass for covetous, while he who gave him a crown, would be reckoned generous; so that the difference of those two opposite characters, turns upon one shilling.
    Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)