diff --git a/src/plfa/part1/Relations.lagda.md b/src/plfa/part1/Relations.lagda.md
index bd1640a7..3bf76ef2 100644
--- a/src/plfa/part1/Relations.lagda.md
+++ b/src/plfa/part1/Relations.lagda.md
@@ -673,7 +673,7 @@ data even where
 
 data odd where
 
-  suc   : ∀ {n : ℕ}
+  suc  : ∀ {n : ℕ}
     → even n
       -----------
     → odd (suc n)