1 files changed, 29 insertions, 2 deletions

diff --git a/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/NonEmptyCardinalityInterval.java b/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/NonEmptyCardinalityInterval.java
index 38bd53bf..6bd66df7 100644
--- a/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/NonEmptyCardinalityInterval.java
+++ b/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/NonEmptyCardinalityInterval.java
@@ -5,6 +5,7 @@
  */
 package tools.refinery.store.representation.cardinality;
 
+import java.util.Objects;
 import java.util.function.BinaryOperator;
 import java.util.function.IntBinaryOperator;
 
@@ -53,6 +54,16 @@ public record NonEmptyCardinalityInterval(int lowerBound, UpperCardinality upper
                 return lift(other, Math::min, UpperCardinality::max, this);
         }
 
+        @Override
+        public CardinalityInterval take(int count) {
+                int newLowerBound = Math.max(lowerBound - count, 0);
+                var newUpperBound = upperBound.take(count);
+                if (newUpperBound == null) {
+                        return CardinalityIntervals.ERROR;
+                }
+                return CardinalityIntervals.between(newLowerBound, newUpperBound);
+        }
+
         private CardinalityInterval lift(CardinalityInterval other, IntBinaryOperator lowerOperator,
                                                                          BinaryOperator<UpperCardinality> upperOperator,
                                                                          CardinalityInterval whenEmpty) {
@@ -73,7 +84,23 @@ public record NonEmptyCardinalityInterval(int lowerBound, UpperCardinality upper
 
         @Override
         public String toString() {
-                var closeBracket = upperBound instanceof UnboundedUpperCardinality ? ")" : "]";
-                return "[%d..%s%s".formatted(lowerBound, upperBound, closeBracket);
+                if (upperBound instanceof FiniteUpperCardinality finiteUpperCardinality &&
+                                finiteUpperCardinality.finiteUpperBound() == lowerBound) {
+                        return "[%d]".formatted(lowerBound);
+                }
+                return "[%d..%s]".formatted(lowerBound, upperBound);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+                if (this == o) return true;
+                if (o == null || getClass() != o.getClass()) return false;
+                NonEmptyCardinalityInterval that = (NonEmptyCardinalityInterval) o;
+                return lowerBound == that.lowerBound && Objects.equals(upperBound, that.upperBound);
+        }
+
+        @Override
+        public int hashCode() {
+                return lowerBound * 31 + upperBound.hashCode();
         }
 }