diff --git a/src/sets.ts b/src/sets.ts
new file mode 100644
index 0000000..517c391
--- /dev/null
+++ b/src/sets.ts
@@ -0,0 +1,13 @@
+export const union = <T>(a: Set<T>, b: Set<T>) => new Set([...a, ...b]);
+export const intersection = <T>(a: Set<T>, b: Set<T>) =>
+	new Set([...a].filter((x) => b.has(x)));
+export const difference = <T>(a: Set<T>, b: Set<T>) =>
+	new Set([...a].filter((x) => !b.has(x)));
+export const symmetric = <T>(a: Set<T>, b: Set<T>) =>
+	union(difference(a, b), difference(b, a));
+export const isSubsetOf = <T>(a: Set<T>, b: Set<T>) =>
+	[...b].every((x) => a.has(x));
+export const isSupersetOf = <T>(a: Set<T>, b: Set<T>) =>
+	[...a].every((x) => b.has(x));
+export const isDisjointFrom = <T>(a: Set<T>, b: Set<T>) =>
+	!intersection(a, b).size;