feat: multi-object based EQUALS and EXISTS

Adds translator for EQUALS and EXISTS symbols based on the multi-object
formalism. Only diagonal equality links are supported (e.g., distinct nodes may
not be EQUALS with each other).

Also introduces initial model seeds to separate partial interpreter construction
and graph initialization better.

6 files changed, 43 insertions, 0 deletions

diff --git a/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/CardinalityInterval.java b/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/CardinalityInterval.java
index 704ca2fc..b20c685a 100644
--- a/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/CardinalityInterval.java
+++ b/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/CardinalityInterval.java
@@ -18,6 +18,8 @@ public sealed interface CardinalityInterval permits NonEmptyCardinalityInterval,
 
         CardinalityInterval add(CardinalityInterval other);
 
+        CardinalityInterval take(int count);
+
         CardinalityInterval multiply(CardinalityInterval other);
 
         CardinalityInterval meet(CardinalityInterval other);
diff --git a/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/EmptyCardinalityInterval.java b/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/EmptyCardinalityInterval.java
index 49911c29..9e371e21 100644
--- a/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/EmptyCardinalityInterval.java
+++ b/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/EmptyCardinalityInterval.java
@@ -5,6 +5,8 @@
  */
 package tools.refinery.store.representation.cardinality;
 
+// Singleton implementation, because there is only a single empty interval.
+@SuppressWarnings("squid:S6548")
 public final class EmptyCardinalityInterval implements CardinalityInterval {
         static final EmptyCardinalityInterval INSTANCE = new EmptyCardinalityInterval();
 
@@ -43,6 +45,11 @@ public final class EmptyCardinalityInterval implements CardinalityInterval {
         }
 
         @Override
+        public CardinalityInterval take(int count) {
+                return this;
+        }
+
+        @Override
         public CardinalityInterval multiply(CardinalityInterval other) {
                 return this;
         }
diff --git a/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/FiniteUpperCardinality.java b/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/FiniteUpperCardinality.java
index 82afdbbc..acd82beb 100644
--- a/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/FiniteUpperCardinality.java
+++ b/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/FiniteUpperCardinality.java
@@ -6,6 +6,7 @@
 package tools.refinery.store.representation.cardinality;
 
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.function.IntBinaryOperator;
 
@@ -22,6 +23,15 @@ public record FiniteUpperCardinality(int finiteUpperBound) implements UpperCardi
         }
 
         @Override
+        @Nullable
+        public UpperCardinality take(int count) {
+                if (finiteUpperBound < count) {
+                        return null;
+                }
+                return new FiniteUpperCardinality(finiteUpperBound - count);
+        }
+
+        @Override
         public UpperCardinality multiply(UpperCardinality other) {
                 return lift(other, (a, b) -> a * b);
         }
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..2e7780da 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
@@ -53,6 +53,16 @@ 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) {
diff --git a/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/UnboundedUpperCardinality.java b/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/UnboundedUpperCardinality.java
index a5634020..e3a334cd 100644
--- a/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/UnboundedUpperCardinality.java
+++ b/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/UnboundedUpperCardinality.java
@@ -7,6 +7,8 @@ package tools.refinery.store.representation.cardinality;
 
 import org.jetbrains.annotations.NotNull;
 
+// Singleton implementation, because there is only a single countable infinity.
+@SuppressWarnings("squid:S6548")
 public final class UnboundedUpperCardinality implements UpperCardinality {
         static final UnboundedUpperCardinality INSTANCE = new UnboundedUpperCardinality();
 
@@ -20,10 +22,17 @@ public final class UnboundedUpperCardinality implements UpperCardinality {
         }
 
         @Override
+        public UpperCardinality take(int count) {
+                return this;
+        }
+
+        @Override
         public UpperCardinality multiply(UpperCardinality other) {
                 return this;
         }
 
+        // This should always be greater than any finite cardinality.
+        @SuppressWarnings("ComparatorMethodParameterNotUsed")
         @Override
         public int compareTo(@NotNull UpperCardinality upperCardinality) {
                 if (upperCardinality instanceof FiniteUpperCardinality) {
diff --git a/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/UpperCardinality.java b/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/UpperCardinality.java
index 5dbaa922..5600ab4c 100644
--- a/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/UpperCardinality.java
+++ b/subprojects/store/src/main/java/tools/refinery/store/representation/cardinality/UpperCardinality.java
@@ -5,6 +5,8 @@
  */
 package tools.refinery.store.representation.cardinality;
 
+import org.jetbrains.annotations.Nullable;
+
 public sealed interface UpperCardinality extends Comparable<UpperCardinality> permits FiniteUpperCardinality,
                 UnboundedUpperCardinality {
         default UpperCardinality min(UpperCardinality other) {
@@ -17,6 +19,9 @@ public sealed interface UpperCardinality extends Comparable<UpperCardinality> pe
 
         UpperCardinality add(UpperCardinality other);
 
+        @Nullable
+        UpperCardinality take(int count);
+
         UpperCardinality multiply(UpperCardinality other);
 
         int compareToInt(int value);