diff --git a/pkgs/applications/science/logic/prover9/default.nix b/pkgs/applications/science/logic/prover9/default.nix
index 5ef7e721a8f2..129abef0b3d7 100644
--- a/pkgs/applications/science/logic/prover9/default.nix
+++ b/pkgs/applications/science/logic/prover9/default.nix
@@ -31,7 +31,7 @@ stdenv.mkDerivation {
   meta = {
     homepage = "http://www.cs.unm.edu/~mccune/mace4/";
     license = "GPL";
-    description = "Prover9 is an automated theorem prover for first-order and equational logic."
+    description = "Prover9 is an automated theorem prover for first-order and equational logic.";
 
     longDescription = ''
       Prover9 is a resolution/paramodulation automated theorem prover