Interval (mathematics) - Classification of Intervals

Classification of Intervals

The intervals of real numbers can be classified into eleven different types, listed below; where a and b are real numbers, with :

empty:
degenerate:
proper and bounded:
open:
closed:
left-closed, right-open:
left-open, right-closed:
left-bounded and right-unbounded:
left-open:
left-closed:
left-unbounded and right-bounded:
right-open:
right-closed:
unbounded at both ends:

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