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Problem Detail: Is this true? If I change all final states of a given Deterministic Finite Automata to non final states and all non final states to final states then does this new automata represent the complement of the language that Read More …

Problem Detail: Counter machines with two or more counters are typically shown to be equivalent to Turing machines in courses on the theory of computation. However, I have not seen a formal analysis of which languages can be recognized by a Read More …

Problem Detail: In the field of Cryptography and Computation Complexity there is a notion of negligible function. I have some difficulties in understanding intuition behind this notion. The following are some definitions from Chapter 9. Cryptography from the textbook Computation Complexity. Read More …

Problem Detail: If a TM(Turing Machine) accepts NO input string(even the blank), then its language is empty. If a TM ONLY accepts the blank string(meaning that there is nothing on the tape except for the default blank characters), then its language Read More …

Problem Detail: Given a weighted digraph $G=V,E$, and a weight function, $d(u,v)$, one can normally use Dijkstra’s algorithm to obtain the shortest path. What I am interested in, is how to obtain the $2^{nd}$-shortest path, the $3^{rd}$-shortest, and so on. Questions: Read More …

Problem Detail: In a recent CACM article [1], the authors present an implementation for staged functions. They use the term as if it was well-known, and none of the references looks like an obvious introduction. They give a short explanation (emphasis Read More …

Problem Detail: I’m reading Garey & Johnsons “Computers and Intractability” and I’m at the part “Some techniques for solving NP-Completeness”. Here’s the text about Proof by Restriction: Proof by restriction is the simplest, and perhaps most frequently applicable, of our three Read More …

Problem Detail: I took an algorithms class on Coursera. The professor in the video about hash tables said that What’s true is that for non-pathological data, you will get constant time operations in a properly implemented hash table. What does “non-pathological Read More …

Problem Detail: We have many problems, like factorization, that are strongly conjectured, but not proven, to be outside P. Are there any questions with the opposite property, namely, that they are strongly conjectured but not proven to be inside P? Asked Read More …

Problem Detail:  Show that proving 2SAT is not NP-Complete would prove that 3SAT is not in P. Or eqivalently – Show that proving 3SAT is in P would prove that 2SAT is NP-Complete. I can see there is an easy Read More …