Differences
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open_ball [2013/09/08 17:38] nikolaj created |
open_ball [2014/03/21 11:11] |
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- | ===== Open ball ===== | ||
- | ==== Definition ==== | ||
- | | @#88DDEE: $\langle d,X\rangle$ ... metric space | | ||
- | | @#FFBB00: $B:X\times \mathbb R_+^*\to \mathcal P(X)$ | | ||
- | | @#FFBB00: $\langle r,a\rangle \mapsto B_a(r):= \{x\ |\ d(x,a)<r \}$ | | ||
- | |||
- | ==== Discussion ==== | ||
- | === Reference === | ||
- | Wikipedia: [[http://en.wikipedia.org/wiki/Ball_%28mathematics%29|Ball (Mathematics)]] | ||
- | ==== Parents ==== | ||
- | === Requirements === | ||
- | [[Metric]] |