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title: Big Omega Notation
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## Big Omega Notation
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Similar to [big O](https://guide.freecodecamp.org/computer-science/notation/big-o-notation) notation, big Omega(Ω) function is used in computer science to describe the performance or complexity of an algorithm.
If a running time is Ω(f(n)), then for large enough n, the running time is at least k⋅f(n) for some constant k. Here's how to think of a running time that is Ω(f(n)):
We say that the running time is "big-Ω of f(n)." We use big-Ω notation for **asymptotic lower bounds**, since it bounds the growth of the running time from below for large enough input sizes.
### Difference between Big O and Big Ω
The difference between Big O notation and Big Ω notation is that Big O is used to describe the worst case running time for an algorithm. But, Big Ω notation, on the other hand, is used to describe the best case running time for a given algorithm.
#### More Information:
- [Big-Ω (Big-Omega) notation](https://www.khanacademy.org/computing/computer-science/algorithms/asymptotic-notation/a/big-big-omega-notation)
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