GoKawiilWhat is this?
This is a calculator that works over unions of intervals rather than just real numbers. It is an implementation of Interval Union Arithmetic.
An interval [a, b] represents the set of all numbers between and including a and b. An interval union: [a, b] U [c, d] is a disjoint set of intervals.
Interval union arithmetic is an extension of regular interval arithmetic that is vastly superior, mostly because it remains closed while supporting division by intervals containing zero:
➤ 2 / [-2, 1] [-∞, -1] U [2, +∞]
The interesting thing about interval union arithmetic is the inclusion property, which means that if you pick any real number from every input union and compute the same expression over the reals, the result is guaranteed to be in the output union.
You can use it to represent uncertainty:
➤ 50 * (10 + [-1, 1]) [450, 550]
You can also compute more complex interval expressions, using the interval union operator U :
➤ ( [5, 10] U [15, 16] ) / [10, 100] [0.05, 1.6]
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