regular expression for strings - infinite case [closed]
Consider the finite alphabet $\{a,b,c\}$.
What is the $\omega-regular$ expression for the language defined by Subsequence containing "ab" occurs not infinite times?
For instance, the string: “bbbbababababccccabbbb...” Which “ab” happens a few times and “b” happens infinite times.
No guarentee, but this expression should work: $$ (a,b,c)^*\Bigl(\bigl((b, c)(b \cup a^*c)^* \cup a(a^*c(b \cup a^*c)^* \cup 1)\bigr)a^*\Bigr)^\omega $$