Empty sum
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Not to be confused with Zero sum.
In mathematics, the empty sum, or nullary sum, is the result of adding no numbers, in summation for example. Its numerical value is zero.
This fact is especially useful and helpful in discrete mathematics and algebra. A simple, well known case is that 0a = 0 — multiplication of any number a by zero always results in zero, because we have added zero copies of a. The empty sum is contrasted with the empty product — the product of no numbers — whose value is not zero, but one.
[edit] References
- A.E. Ingham, contributor R C Vaughan, The Distribution of Prime Numbers, Cambridge University Press, 1990, ISBN 0-521-39789-8
