Problem Detail: This is a question from a text book that’s giving me some trouble. The question is: Determine whether or not this language is regular. Justify your answer. $$L = {ww : w in {a,b}^* }$$ I think this language Read More …
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Is this grammar LR(1)
Problem Detail: I am reading parser chapter from dragon book and I found a grammar over there – $ S rightarrow L=R $ $ S rightarrow R $ $L rightarrow *R $ $L rightarrow id $ $R rightarrow L $ Now Read More …
How are all NP Complete problems similar?
Problem Detail: I’m reading few proofs which prove a given problem is NP complete. The proof technique has following steps. Prove that current problem is NP, i.e., given a certificate, prove that it can be verified in polynomial time. Take any Read More …
Convex polygon formulation
Problem Detail: We have a sorted list of side lengths that can be used to form a polygon. There are $n$ such values ($n le 1000$). Now we need to find if we can use any 10 of these values to Read More …
Deriving the Sobel equations from derivatives
Problem Detail: Many sites give the Sobel operators as the convolution mask for smoothing an image. However, I haven’t found a single site that describes how you can derive the operators from partial first derivatives. If anyone can explain the derivation, Read More …
Why is Relativization a barrier?
Problem Detail: When I was explaining the Baker-Gill-Solovay proof that there exists an oracle with which we can have, $mathsf{P} = mathsf{NP}$, and an oracle with which we can have $mathsf{P} neq mathsf{NP}$ to a friend, a question came up as Read More …
Which algorithms are usable for heatmaps and what are their pros and cons
Problem Detail: This is a cross post from Stack Overflow, and DSP at Stackexchange since I cannot really decide which part of Stackexchange is most fitting. If this is the wrong place please tell me and I’ll remove the question. I Read More …
Local Search vs Classical Search
Problem Detail: I have some questions regarding local search / optimization as explained in chapter 4 of the book : http://aima.cs.berkeley.edu/ In classical search (Chap 3), the search starts from an initial node, then the search continues based on strategies of Read More …
the convention for declaring arrays in pseudocode
Problem Detail: I have a very simple question. What is the right standard convention to use for declaring arrays? I understand that for a simple declaration of a variable as an integer, this is the convention: DECLARE myVar : INTEGER What Read More …
An oracle to separate NP from coNP
Problem Detail: How to prove that $mathsf{NP}^A neq mathsf{coNP}^A$ ? I am just looking for a such oracle TM $M$ and a recursive language $L(M) = L$ for which this holds. I know the proof where you show that there is Read More …
