Closed Disk -- from Wolfram MathWorld
- ️Weisstein, Eric W.
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An 
-dimensional closed disk of radius 
is the collection of points of distance
from a fixed point in 
-dimensional Euclidean space.
Krantz (1999, p. 3) uses the symbol 
to denote the closed disk, and 
to denote the unit closed disk centered at the
origin
See also
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References
Krantz, S. G. Handbook of Complex Variables. Boston, MA: Birkhäuser, p. 3, 1999.
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Cite this as:
Weisstein, Eric W. "Closed Disk." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/ClosedDisk.html