independence number

independence number (plural independence numbers)

1. (graph theory) The number of vertices in a maximum independent set of a given graph, often denoted as ${\displaystyle \alpha =\alpha (G)}$.
2. (set theory) The smallest cardinality of a maximal independent family of subsets of the natural numbers, usually denoted by lowercase Fraktur letter ${\displaystyle {\mathfrak {i}}}$.