Minor-Closed Property

The Minor-Closed Property refers to a key concept in graph theory, specifically dealing with the structure of graphs. A property is "minor-closed" if, whenever a graph has that property, any graph obtained from it by removing vertices or edges also has the same property. For example, if a certain type of graph, like a planar graph (which can be drawn on a flat surface without edges crossing), has the minor-closed property, then any smaller graph derived from it by deletion will also be planar. This principle helps mathematicians understand the characteristics and behaviors of graphs in more complex forms.