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Plane Division by Ellipses


PlaneDivisionbyEllipses

Plane division by ellipses is the partition of the plane into regions by an arrangement of n ellipses, where n is a nonnegative integer. For n>=1, the maximal number of regions is

 N(n)=2n^2-2n+2=2(n^2-n+1),

giving values for n=1, 2, ... of 2, 6, 14, 26, 42, 62, 86, 114, ... (OEIS A051890).

The maximum is attained when each pair of ellipses intersects in four distinct points and no three ellipses pass through the same point. For n>=2, the nth ellipse then adds 4(n-1) regions. With no ellipses, N(0)=1.


See also

Arrangement, Circle Division by Lines, Ellipse, Plane Division by Circles, Plane Division by Lines

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References

--. Problem Q607. Parabola 20, 27, 1984.Sloane, N. J. A. Sequence A051890 in "The On-Line Encyclopedia of Integer Sequences."

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Plane Division by Ellipses

Cite this as:

Weisstein, Eric W. "Plane Division by Ellipses." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/PlaneDivisionbyEllipses.html

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