Problem Detail: Codd’s Algorithm converts an expression in tuple relational calculus to Relational Algebra. Is there a standard implementation of the algorithm? Is this algorithm used anywhere? (It seems that the industry only needs SQL and variants, I’m not sure about Read More …
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[Solved]: Equality testing of arrays and integers in a procedural language
Problem Detail: In terms of references and their implementation on the heap and the stack, how is equality testing for arrays different from that for integers? This is to do with Java programming, if you have a stack and a heap, Read More …
[Solved]: Modification of Hamilton Path
Problem Detail: Although I know that the Hamilton Path problem is ${sf NP}$-complete, I think the following variant can be solved in polynomial time: Given a planar graph with vertex set $V$, edge set $E$, start node $S$ and target node Read More …
[Solved]: What does it mean to say that there doesn’t exist an algorithm from a TM point of view?
Problem Detail: A TM for a recursive language corresponds to our informal notion of an algorithm. as per Automata Theory, Languages and Computation by Ullman et al. Then there are languages called RE and $L_d$, where there exist TM that Read More …
[Solved]: What is a fixed point in the context of Roger’s fixed-point theorem?
Problem Detail: In the Wikipedia article on Rogers’ theorem, it is stated that all total computable functions have a fixed point. The notation is a little hard for me to understand; a symbol is used that is used to denote “semantic Read More …
[Solved]: Optimal upper bound on the number of states in the complement of an NFA
Problem Detail: I have my own version of lex and I would like to add the complement operation. Derived from that I can then add the intersection and difference also. My version also supports the generation of NFAs (Non-deterministic Finite Automaton) Read More …
[Solved]: Proof of big theta using induction
Problem Detail: Here is a recursive definition for the runtime of some unspecified function. $a$ and $c$ are positive constants. $T(n) = a$, if $n = 2$ $T(n) = 2T(n/2) + cn$ if $n > 2$ Use induction to prove that Read More …
[Solved]: Sorting numbers in $O(1)$
Problem Detail: Here is an experiment I came up with (I don’t have sufficient material to make it): Say that, you have a list of $n$ numbers $L = {l_1, l_2, …, l_n}$. And you have bars representing those numbers like Read More …
[Solved]: 2 cases for P = NP
Problem Detail: As we all know the million dollar question in Computer Science P=NP or not. I was trying to understand it and got some doubts please tell me whether I’m right or wrong N=NP in two cases Case 1: We Read More …
[Solved]: $2k$ number assignment
Problem Detail: Given $k$ numbers $A_1 leq A_2 leq … leq A_k$ such that $sumlimits_{i=1}^k A_i = k(2k + 1)$ is there an assignment of numbers $i_1, i_2, … , i_{2k}$ which is a permutation of $1, 2, … , 2k$ Read More …
