Problem Detail: I would like some hints on how to approach this problem, I know for instance that $TQBF$ is $PSPACE$-$Complete$, so it can solved in poly space and any other $PSPACE$-$Complete$ problems can be log spaced reduced to $TQBF$. I Read More …
Blog
[Solved]: Proving that any CF language over a 1 letter alphabet is regular
Problem Detail: I would like to prove that any context free language over a 1 letter alphabet is regular. I understand there is Parikh’s theorem but I want to prove this using the work I have done so far: Let L Read More …
[Solved]: Writing a multitasking operating system for a processor without MMU
Problem Detail: I’ve been thinking of writing a hobby operating system for some of the ARM processors. There are many popular single-board computers with ARM MPU, so I simply wanted to purchase one of those (choosing one with more open documentation). Read More …
[Solved]: What helpful solution does the Halting Problem give to computing?
Problem Detail: What problem does the halting problem solve in computing, whether theoretical or practical? It is very easy to debug code which loops forever, just signal the debugger to break if the program is running for too long? What purpose Read More …
[Solved]: Can a CFG end have a non-terminal symbol in the middle of it?
Problem Detail: What is the correct way to write a CFG? A -> B C’ E C’ -> C C’ -> null or A -> B C’ C’ -> C E C’ -> E Asked By : Badger Cat Answered By : usul Read More …
[Solved]: Do all states in a DFA must be connected?
Problem Detail: Could I construct (for some wired reason) a DFA that has a state that is not connected to anything, and it would still be legal? I’m studying for a test, and I found a question that asks if an Read More …
[Solved]: How to reduce MAX-2SAT problem to finding a cut in a graph
Problem Detail: I’m trying to reduce the MAX-2SAT problem to finding a cut in a graph, with no luck so far. Let me first show a description of the problem: 2SAT: Given a boolean formula $varphi$ in a CNF form, where Read More …
[Solved]: Can we push and pop both at a single transition in a PDA?
Problem Detail: Let say I have a pda : δ(q1,a,Z)=(q2,aZ) δ(q2,a,aZ)=(q2,bZ) Is this allowed…. you can see that in δ(q2,a,aZ)=(q2,bZ), we are basically popping ‘a’ and pushing ‘b’ for a single transition… Is this allowed for PDA ?? Asked By : Shubham Read More …
[Solved]: Is CYK still relevant today?
Problem Detail: I’ve come across the CYK algorithm and was wondering, as it’s quite old, if it is still relevant today. Is it or an extension of it still being used in compilers (for example), or have other algorithms proven to Read More …
MCS021 Decemeber 2015 Solved Question Paper
Download Solutions
