Update 'README.md'

README.md

@@ -73,6 +73,7 @@ ___
 - [Ostracon](https://en.wikipedia.org/wiki/Ostracon)
 - [Sci Hub](https://sci-hub.se/)
 - [Eugene Wigner](https://en.wikipedia.org/wiki/Eugene_Wigner)
+- [Exponential Time Hypothesis](https://en.wikipedia.org/wiki/Exponential_time_hypothesis)
 
 ## [Mathematics and Theoretical Computer Science](mathematics.md)
 - [OEIS: The Online Encyclopedia of Integer Sequences](https://oeis.org/)