Problem Detail: Can $R$ be inferred from $P$, $Q$, and $(P to Q) to R$ using only modus ponens? My understanding is that it can, as shown below, but I was told this was incorrect. Proof of ${P, Q, (P to Read More …
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[Solved]: How to write a many-one reduction proof
Problem Detail: Writing a proof by contradiction is fairly formulaic–first you assume the opposite, then derive a contradiction. I would like to know the steps and conventions for writing a many-one reduction proof. This answer was somewhat helpful, but like other Read More …
[Solved]: Big-Endian/Little-Endian argument – paper by Danny Cohen
Problem Detail: Reading a book I was redirected to “On holy wars and a plea for peace” paper by Danny Cohen, which covers the “holy war” between big-endians and little-endians considering byte-order. Reaching the summary of the memory section I got Read More …
[Solved]: What is the difference between oblivious and non-oblivious merging, sorting etc
Problem Detail: Algorithms can either be oblivious or non-oblivious, but what is the actual difference between the two? Asked By : Summer Answered By : Evil Oblivious means that the control flow is independent of some properties of data. For example Bitonic Sort Read More …
[Solved]: Does every large enough string have repeats?
Problem Detail: Let $Sigma$ be some finite set of characters of fixed size. Let $alpha$ be some string over $Sigma$. We say that a nonempty substring $beta$ of $alpha$ is a repeat if $beta = gamma gamma$ for some string $gamma$. Read More …
[Solved]: is determinism = non determinism for one counter automata?
Problem Detail: This language I think is not accepted by a deterministic one counter but accepted by a non-deterministic one counter : $L = {a^{i}b^{j}c^{k} mid (i=j) vee (j=k) text{ such that } igeq0, jgeq0, kgeq0}$ But how to prove this Read More …
[Solved]: Does exploiting a spatial Locality in Cache always leads to a lower miss rate?
Problem Detail: I’ve read that, incorporating many words(spatial locality) per cache blocks leads to lower miss rate. Is it the case always? One possibility of such approach is to make a single cache block of size equal to the size of Read More …
[Solved]: Sequential numbers to unique-looking numbers
Problem Detail: I’m not sure how to word this because I’m not familiar with this, but I’m sure a process like this is rather common. Basically, I’ve got members signing up for our website, and each one is assigned a normal Read More …
[Solved]: An one-sentence proof of P ⊆ NP
Problem Detail: Recently I am reading a document [1]. In this document, Prof. Cook provides a brief proof of $mathbf{P} subseteq mathbf{NP}$, which is only one sentence: It is trivial to show that $mathbf{P} subseteq mathbf{NP}$, since for each language $L$ Read More …
[Solved]: String Comparison vs. Hashing
Problem Detail: I recently learned about the rolling hash data structure, and basically one of its prime uses to searching for a substring within a string. Here are some advantages that I noticed: Comparing two strings can be expensive so this Read More …
