Inversion (discrete mathematics)

Inversion in a sequence refers to a pair of numbers that are "out of order" with respect to an ascending or descending order.

Formally, let $A[1..n]$ be an array of $n$ distinct numbers. If $i<j$ and $A[i]>A[j]$, then the pair $(i,j)$ is called an inversion of $A$.

• Cormen, Thomas H. (2001). Introduction to Algorithms (2nd ed.). MIT Press and McGraw-Hill. ISBN 0-262-53196-8. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)