1 files changed, 22 insertions, 0 deletions

diff --git a/subprojects/logic/src/main/java/tools/refinery/logic/dnf/FunctionalDependency.java b/subprojects/logic/src/main/java/tools/refinery/logic/dnf/FunctionalDependency.java
new file mode 100644
index 00000000..c3fc87ab
--- /dev/null
+++ b/subprojects/logic/src/main/java/tools/refinery/logic/dnf/FunctionalDependency.java
@@ -0,0 +1,22 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package tools.refinery.logic.dnf;
+
+import tools.refinery.logic.InvalidQueryException;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public record FunctionalDependency<T>(Set<T> forEach, Set<T> unique) {
+        public FunctionalDependency {
+                var uniqueForEach = new HashSet<>(unique);
+                uniqueForEach.retainAll(forEach);
+                if (!uniqueForEach.isEmpty()) {
+                        throw new InvalidQueryException("Variables %s appear on both sides of the functional dependency"
+                                        .formatted(uniqueForEach));
+                }
+        }
+}