Update README.md

README.md

@@ -42,7 +42,7 @@ Statistical Description
 The descended articles correspond to a portion of the articles that had their last modifications in the year 2023 on the arXiv platform.
 
 | Number of                                 |           |
-| :----------------------------------------:|-----------|
+| -----------------------------------------:|:----------|
 | articles                                  | 22,397    |
 | authors                                   | 50,000    |
 | figures                                   | 157,944   |