diff --git a/2024-12-28.md b/2024-12-28.md
index 631fcb8b5..75ee63510 100644
--- a/2024-12-28.md
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@@ -13,3 +13,4 @@
   - [[ai]]
   - [[sustainability]]
   - leading to [[ilich]], who I still haven't read -- will try to set up his book in my [[kobo]] to read it tonight/soon
+- I read about [[recursively enumerable]] sets and languages -- I remembered these were some of my favorite back when I studied computer science when I was 27 or 28. This led me to read again about complexity classes, hierarchies and then [[diophantine]] sets :)