HittingSetModule.hs

A Haskell HittingSetModule.hs module exporting a function that finds the solution to the basic variant of the HittingSet problem: The function takes in a moderate-size family of moderate-size sets of integers, and it slowly returns the corresponding lexicographically minimal blocking set of minimum cardinality.

In the spirit of Theorem 9.12(ii) and Example 9.13 from the monograph A.O. Matveev, Symmetric Cycles, Jenny Stanford Publishing, 2023.

Blocking Sets

Let $\mathcal{A} := \langle A_1, A_2, ..., A_k\rangle$ be a nonempty family of nonempty subsets of a finite set $E$. A subset $B$ of the set $E$ is called a blocking set (or hitting set, transversal, vertex cover (or node cover), system of representatives) of the family $\mathcal{A}$ if and only if the set $B$ has a nonempty intersection with each set $A_i$ from the family $\mathcal{A}$.