diff --git a/metadata/topics b/metadata/topics
--- a/metadata/topics
+++ b/metadata/topics
@@ -1,44 +1,45 @@
 Computer Science
   Automata and Formal Languages
   Algorithms
     Distributed
     Concurrent
     Online
   Concurrency
     Process Calculi
   Data Structures
   Functional Programming
   Games
   Hardware
   Networks
   Programming Languages
     Language Definitions
     Lambda Calculi
     Type Systems
     Logics
     Compiling
     Static Analysis
     Transformations
     Misc
   Security
     Cryptography
   Semantics
   System Description Languages
 Logic
   Philosophy
   Rewriting
 Mathematics
   Order
   Algebra
   Analysis
   Probability Theory
   Number Theory
   Economics
   Geometry
   Topology
   Graph Theory
   Combinatorics
   Category Theory
   Physics
+  Set Theory
   Misc
 Tools