diff --git a/src/node.hpp b/src/node.hpp
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+/* node.hpp: Definition of fractions and nodes on the Calkin-Wilf tree
+ * Created: 2025-11-27
+ * Author: Aryadev Chavali
+ * License: See end of file
+ * Commentary:
+ */
+
+#ifndef NODE_HPP
+#define NODE_HPP
+
+#include <string>
+#include <vector>
+
+#include "base.hpp"
+
+namespace cw::node
+{
+  struct Fraction
+  {
+    u64 numerator, denominator; // always simplified
+    f64 norm;
+
+    Fraction(u64 numerator = 0, u64 denominator = 1);
+
+    // Complete ordering on Fractions
+    bool operator<(const Fraction other);
+    bool operator==(const Fraction &other);
+  };
+
+  std::string to_string(const Fraction &);
+
+  struct Node
+  {
+    Fraction value;
+    index_t left, right;
+
+    Node(const Fraction &&val = {}, index_t left = -1, index_t right = -1);
+  };
+
+  std::string to_string(const Node &);
+
+  struct NodeAllocator
+  {
+    std::vector<Node> vec;
+
+    NodeAllocator(u64 capacity = 256);
+    u64 alloc(Node n);
+    Node get_val(u64 n) const;
+    Node &get_ref(u64 n);
+  };
+
+  std::string to_string(const NodeAllocator &, const index_t, int depth = 1);
+} // namespace cw::node
+
+#endif
+
+/* Copyright (C) 2025 Aryadev Chavali
+
+ * 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 Version 2 for
+ * details.
+
+ * You may distribute and modify this code under the terms of the GNU General
+ * Public License Version 2, which you should have received a copy of along with
+ * this program.  If not, please go to <https://www.gnu.org/licenses/>.
+
+ */