1 files changed, 37 insertions, 0 deletions
diff --git a/proofsearch/src/simplify/tautology.cc b/proofsearch/src/simplify/tautology.cc
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+++ b/proofsearch/src/simplify/tautology.cc
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+/*
+ * richard-atp-engine: A saturation-based automated theorem prover for first-order logic.
+ * Copyright (C) 2026 Richard Qin
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "atp/simplify/tautology.h"
+
+#include "atp/core/clause.h"
+
+#include <cstddef>
+
+namespace atp {
+bool isTautology(const Clause& clause) {
+    for (size_t i = 0; i < clause.size(); ++i) {
+        for (size_t j = i + 1; j < clause.size(); ++j) {
+            if (clause.literals_[i].atom_ == clause.literals_[j].atom_ &&
+                clause.literals_[i].is_positive_ != clause.literals_[j].is_positive_) {
+                return true;
+            }
+        }
+    }
+    return false;
+}
+}  // namespace atp
+\ No newline at end of file