Ε-net (computational geometry): Difference between revisions

Content deleted Content added
I think the original writer wanted P to be the particular rectangle, not the given region. As in the example and even in the theory before that, P as the given region doesn't seem correct.
Background: clean up - WP:ACCIM rule #6 using AWB
Line 19:
| year = 1987}}.</ref> In other words, any range that intersects at least a proportion ε of the elements of ''P'' must also intersect the ''ε''-net&nbsp;''N''.
 
For example, suppose ''X'' is the set of points in the two-dimensional plane, ''R'' is the set of closed filled rectangles (products of closed intervals), and ''P'' is the unit square [0,&nbsp;1]&nbsp;×&nbsp;[0,&nbsp;1]. Then the set N consisting of the 8 points shown in the adjacent diagram to the right is a 1/4-net of P, because any closed filled rectangle intersecting at least 1/4 of the unit square must intersect one of these points. In fact, any (axis-parallel) square, regardless of size, will have a similar 8-point 1/4-net.
 
For any range space with finite [[VC dimension]] ''d'', regardless of the choice of P, there exists an ε-net of ''P'' of size