Update 'backlog.md'

backlog.md

@@ -60,6 +60,7 @@
 - [Nim](https://en.wikipedia.org/wiki/Nim)
 - [AS WE MAY THINK by VANNEVAR BUSH](http://web.mit.edu/STS.035/www/PDFs/think.pdf)
 - [Dice Problem](https://blog.computationalcomplexity.org/2024/01/a-nice-dice-problem-part-2.html)
+- [Polynomials and RE](https://blog.computationalcomplexity.org/2024/01/certifying-number-is-in-set-using.html)
 
 ## Reference Book Backlog
 - Bartlett's Familiar Quotations