Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works

degree sequence

The list of every vertex's degree, sorted, used to check whether a degree list can come from a real graph.

A graph's degree sequence lists every vertex's degree, usually sorted in decreasing order; a sequence is graphical if some simple graph actually realizes it.