a. Input: halfspaces H and partial basis (planes) B b. Sentinel constraints c. Incremental algorithm d. Correctness: violated constraint must be in the optimal basis e. Worst-case analysis: O(n^d) time f. Randomized analysis: ≤ (e-1)·d!·n expected violation tests, O(d·d!·n) expected time g. Minimum-area enclosing annulus