In mathematics, the ε-covering number of a metric space (X, d), for some ε > 0, is the minimum number of balls of radius that are needed to cover X.
A related concept is the ε-packing number which is defined as the maximum number of disjoint balls of radius ε that fit into X.
Famous quotes containing the words covering and/or number:
“Three forms I see on stretchers lying, brought out there untended
lying,
Over each the blanket spread, ample brownish woolen blanket,
Gray and heavy blanket, folding, covering all.”
—Walt Whitman (1819–1892)
“I think, for the rest of my life, I shall refrain from looking up things. It is the most ravenous time-snatcher I know. You pull one book from the shelf, which carries a hint or a reference that sends you posthaste to another book, and that to successive others. It is incredible, the number of books you hopefully open and disappointedly close, only to take down another with the same result.”
—Carolyn Wells (1862–1942)