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In page Interval (mathematics):

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Allowing for a mix of open, closed, and infinite endpoints, the Cartesian product of any n {\displaystyle n} intervals, I = I 1 × I 2 × × I n {\displaystyle I=I_{1}\times I_{2}\times \cdots \times I_{n}} is sometimes called an n {\displaystyle n} -dimensional interval.[citation needed]