I'm not sure where to ask questions about theoretical stuff. I don't want to get down-voted for asking at the wrong place. Also what is the difference between programmers.stackexchange and stackoverflow? Are you supposed to use both for different types of questions?
From their help center:
What topics can I ask about here?
Theoretical Computer Science Stack Exchange is a Q&A site for professional researchers in theoretical computer science and related fields. We welcome research-level questions in theoretical computer science (TCS).
What do you mean by "research-level question"?
Although there is no black-and-white distinction between research-level questions and non-research-level questions, questions are considered to be "research-level" roughly when they can be discussed between two professors or between two graduate students working on Ph.D.'s, but not usually between a professor and a typical undergraduate student. It does not include questions at the level of difficulty of typical undergraduate course/textbook homework/exercise.
What do you mean by "theoretical computer science"?
For an explanation of what TCS is, we refer you to the description of ACM Special Interest Group on Algorithms and Computation Theory (SIGACT):
TCS covers a wide variety of topics including algorithms, data structures, computational complexity, parallel and distributed computation, probabilistic computation, quantum computation, automata theory, information theory, cryptography, program semantics and verification, machine learning, computational biology, computational economics, computational geometry, and computational number theory and algebra.
Work in this field is often distinguished by its emphasis on mathematical technique and rigor.