Update seminar.md

seminar.md

@@ -54,7 +54,7 @@ and a mattermost channel for chat. To join the mattermost channel:
 |2021-03-01| Bernhard Schröder | Framed proofs -- Linguistic aspects of proof texts and frames |
 |2021-03-15| Peter Koepke | Isabelle/Naproche |
 |2021-03-29| André Greiner-Petter | Comparative Verification of Digital Mathematical Libraries and Computer Algebra Systems ([slides](https://gist.github.com/AndreG-P/4fdbd42f313d112c888c10c2136a3620)) |
-|2021-04-12| Deyan Ginev | TBA |
+|2021-04-12| Deyan Ginev | Scientific Statement Classification over arXiv.org ([slides](https://prodg.org/talks/scientific_statement_classification#1)) |
 |2021-04-26| ? | ? |
 |2021-05-10| ? | ? |
 |2021-05-24| ? | May be cancelled (public holiday after pentecoast at least in Germany) |