From 6e974168ecc487d99cbe51df569d52304907900c Mon Sep 17 00:00:00 2001
From: Richard Qin <richard.qin.x@gmail.com>
Date: Sat, 4 Apr 2026 03:02:48 +0800
Subject: feat: implement clause subsumption and tautology detection logic with
 associated unit tests

---
 src/simplify/subsumption.cc | 23 +++++++++++++++++++++++
 src/simplify/tautology.cc   | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+)
 create mode 100644 src/simplify/tautology.cc

(limited to 'src')

diff --git a/src/simplify/subsumption.cc b/src/simplify/subsumption.cc
index b62ffd0..cf243c9 100644
--- a/src/simplify/subsumption.cc
+++ b/src/simplify/subsumption.cc
@@ -16,4 +16,27 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+#include "atp/simplify/subsumption.h"
 
+
+namespace atp {
+
+    bool subsumes(const Clause& general, const Clause& specific) {
+        if (general.size() > specific.size()) {
+            return false;
+        }
+        for (const auto& lit_g : general.literals) {
+            bool found = false;
+            for (const auto& lit_s : specific.literals) {
+                if (lit_g.atom == lit_s.atom && lit_g.is_positive == lit_s.is_positive) {
+                    found = true;
+                    break;
+                }
+            }
+            if (!found) {
+                return false;
+            }
+        }
+        return true;
+    }
+}
diff --git a/src/simplify/tautology.cc b/src/simplify/tautology.cc
new file mode 100644
index 0000000..d41ecd7
--- /dev/null
+++ b/src/simplify/tautology.cc
@@ -0,0 +1,34 @@
+/*
+ * 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 <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;
+    }
+}
\ No newline at end of file
-- 
cgit v1.2.3