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I am studying the complexity of SAT resolution refutation. There is a useful tool named weakening rule > T[he weakening rule][1]: B -->B ∨ C says that from a clause B we can derive the weaker clause B ∨ C for an arbitrary C. We say that B ∨ C is a weakening of B. We can add this extra rule without loss of gene...
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For a given number of steps, the $\delta$ is $$\delta=\frac{x_e-x_s}{n}$$ and you have the constraints $\delta\le\delta_{\max},n\le n_{\max}$ (if I understand anything of your question). So $$\left\lceil\frac{x_e-x_s}{\delta_{\max}}\right\rceil\le n\le n_{\max}.$$ ---------- There is only a solution ...
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Since your types both reference each other, these are not inductive types, but [coinductive types](https://cs.stackexchange.com/questions/525/what-is-coinduction).$^{1}$ That's because, if you expand out T1 and T2 (as you have done partially in the question), you get an infinite structure: ``` T1 = { a: int, { a: int...
The usual many-one reduction involves Turing machines transforming an input, $w$, of some language to an input, $f(w)$, of some other language in polynomial time. (Where $w \in L_1 \iff f(w) \in L_2$). But for $P$-completeness, logspace or NC reductions are often used instead (taken from [wikipedia](https://en.wikip...
Are any known problems complete for $P$ under "$O(1)$ reductions?"
|complexity-theory|polynomial-time|constant-time|
What component and mechanism determines which DMA transfer mode is used? How can be identified what DMA mode is used by a device, let's say on Linux? Let's consider a contemporary AMD or Intel x86-64 system with two DMA devices. Device 1 is an input device that regularly DMA writes for 300 microseconds (most lik...
DMA mode: burst or cycle stealing -- how to know and set? What is blocked?
|cpu|memory-hardware|memory-access|
What component and mechanism determines which DMA transfer mode is used? How can be identified what DMA mode is used by a device, let's say on Linux? Let's consider a contemporary AMD or Intel x86-64 system with two DMA devices. Device 1 is an input device that regularly DMA writes for 300 microseconds (most lik...
What component and mechanism determines which DMA transfer mode is used? How can be identified what DMA mode is used by a device, let's say on Linux? Let's consider a contemporary AMD or Intel x86-64 system with two DMA devices. Device 1 is an input device that regularly DMA writes for 300 microseconds (most lik...
What component and mechanism determines which DMA transfer mode is used? How can be identified what DMA mode is used by a device, let's say on Linux? Let's consider a contemporary AMD or Intel x86-64 system with two DMA devices. Device 1 is an input device that regularly DMA writes for 300 microseconds (I'm gues...
What component and mechanism determines which DMA transfer mode is used? How can be identified what DMA mode is used by a device, let's say on Linux? Let's consider a contemporary AMD or Intel x86-64 system with two DMA devices. Device 1 is an input device that regularly DMA writes for 300 microseconds (I'm gues...
What component and mechanism determines which DMA transfer mode is used? How can be identified what DMA mode is used by a device, let's say on Linux? Let's consider a contemporary AMD or Intel x86-64 system with two DMA devices. Device 1 is an input device that regularly DMA writes for 300 microseconds (I'm gues...
What component and mechanism determines which DMA transfer mode is used? How can be identified what DMA mode is used by a device, let's say on Linux? Let's consider a contemporary AMD or Intel x86-64 system with two DMA devices. Device 1 is an input device that regularly DMA writes for 300 microseconds (I'm gues...
In this question I need your help researching time complexity of a dynamic array with insert-last() and delete-last() operations: We define a data structure and call it dynamic array, we define the operations inseet-last() and delete-last(), we also define a set of rules for this data structure: 1. When the data ...
Researching the complezity of a dynamic array with insert-last() and delete-last() operations
|time-complexity|data-structures|asymptotics|arrays|
Researching the complexity of a dynamic array with insert-last() and delete-last() operations
I have a matrix (input): | -- | c1 | c2 | c3 | |:--:|:--:|:--:|:--:| | r1 | AA | BB | CC | | r2 | CC | RR | BB | | r3 | EE | DD | FF | | r4 | KK | DD | EE | | r5 | DD | GG | KK | | r6 | PP | QQ | KK | 1. Let's call each matrix cell a `namespace`. If two rows begin from the same namespace, then such a names...
What component and mechanism determines which DMA transfer mode is used? How can be identified what DMA mode is used by a device, let's say on Linux? Let's consider a contemporary AMD or Intel x86-64 system with two DMA PICe devices. Device 1 is an input device that regularly DMA writes for 300 microseconds (I...
Let C be even. Take C items where $w_{ij} = 1$ and C items where $w_{ij} = 2$. Your greedy algorithm will put the same C items in each bin, so you find a solution with C items. Instead you can put C items of size 1 into bin 1, then C/2 items each of size 2 into bin 2 and bin 3, giving a solution where you get C ite...
I couldn't find any answer to the question online but i think i figure it out. 1- when you type on your keyboard any alphabetical letters, you actually sending a binary code NOT the letter itself. So... 2- the alu of the computer it is a hardware circuits which takes the instructions it is based on and execute t...
I often hear NP-completeness as problems such that, if they were in $P$ all problems in $NP$ are in $P$. The true definition, though, is that NP-complete is a set of languages that all languages in NP reduce to in polynomial time (Cook reduction). But is this idea that NP-completeness implies all problems are in P i...
Is finding a Cook reduction from $L_1$ to $L_2$ equivalent to proving $L_2 \in P \Rightarrow L_1 \in P$
|complexity-theory|reductions|polynomial-time|polynomial-time-reductions|
|complexity-theory|reductions|logic|polynomial-time|polynomial-time-reductions|
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In this question I need your help researching time complexity of a dynamic array with insert-last(x) and delete-last() operations: We define a data structure and call it dynamic array, we define the operations inseet-last(x) and delete-last(), we also define a set of rules for this data structure: Insert-last(x):...
Researching the complexity of a dynamic array with insert-last(x) and delete-last() operations
I often hear NP-completeness as problems such that, if they were in $P$ all problems in $NP$ are in $P$. The true definition, though, is that NP-complete is a set of languages that all languages in NP reduce to in polynomial time. But is this idea that NP-completeness implies all problems are in P if they are in P a...
Is finding a Polytime reduction from $L_1$ to $L_2$ equivalent to proving $L_2 \in P \Rightarrow L_1 \in P$
**Edit:** A **walk** is a finite or infinite sequence of edges which joins a sequence of vertices. A **trail** is a walk in which all edges are distinct. A **cycle** in a graph is a non-empty trail in which only the first and last vertices are equal. We know that determining whether two vertices (or two edges) fall...
What component and mechanism determines which DMA transfer mode is used? How can be identified what DMA mode is used by a device, let's say on Linux? Let's consider a contemporary AMD or Intel x86-64 system with two DMA PCIe devices. Device 1 is an input device that regularly DMA writes for 300 microseconds (I...
I know that, T(m,n) = T(m-1,n) + T(m,n-1) + c it's the recurrence equation of Longest Common Subsequence algorithm. And the time complexity of the LCS in case of recursive method is O(2^n+m). But, how do I derive the time complexity from the above recurrence relation?
How to derive time complexity of the Recurrence Relation - T(m,n) = T(m-1,n) + T(m,n-1) + c
|algorithms|time-complexity|algorithm-analysis|recurrence-relation|recursion|
I know that, *T(n,m) = T(n-1,m) + T(n,m-1) + c* it's the recurrence equation of Longest Common Subsequence algorithm. And the time complexity of the LCS in case of recursive method is O(2^n+m). The base condition is: *when m or n = 0, T(m,n) = 0 i.e., T(0,m)=0 and T(m,0)=0*. But, how do I derive the time complexi...
How to derive time complexity of the Recurrence Relation - T(n,m) = T(n-1,m) + T(n,m-1) + c
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I know that, *T(n,m) = T(n-1,m) + T(n,m-1) + c* it's the recurrence equation of Longest Common Subsequence algorithm. And the time complexity of the LCS in case of recursive method is O(2^n+m). The base condition is: *when m or n = 0, T(m,n) = 1 i.e., T(0,m)=1 and T(m,0)=1*. But, how do I derive the time complexi...
I know that, *T(n,m) = T(n-1,m) + T(n,m-1) + c* it's the recurrence equation of Longest Common Subsequence algorithm. And the time complexity of the LCS in case of recursive method is O(2^n+m). The base condition is: *when m or n = 0, T(m,n) = 1 i.e., T(0,n)=1 and T(m,0)=1*. But, how do I derive the time complexi...
A **walk** is a finite or infinite sequence of edges which joins a sequence of vertices. A **trail** is a walk in which all edges are distinct. A **cycle** in a graph is a non-empty trail in which only the first and last vertices are equal. We know that determining whether two vertices (or two edges) fall on a tria...
I often hear NP-completeness as problems such that, if they were in $P$ all problems in $NP$ are in $P$. The true definition, though, is that NP-complete is a set of languages in NP that all languages in NP reduce to in polynomial time. But is this idea that NP-completeness implies all problems are in P if they are ...
I realized this question is a [duplicate](https://cs.stackexchange.com/questions/6138/problem-with-implementing-brzozowskis-algorithm). Basically, as @Pseudonym mentioned above, when reverting DFA you should avoid introducing new starting state of the NFA even if there were multiply finish states in DFA. Instead jus...
**Hint:** A solution of the homogeneous recurrence is well-known to be $$T(n,m)=\binom{n+m}n=\frac{(n+m)!}{n!\,m!}$$ by Pascal's identity. And a particular solution of the non-homogeneous solution is simply $$T(n,m)=-c.$$
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I have formulated an instance of a 0-1 Integer Program (IP), which I am trying to determine the complexity of (can this instance be solved in polynomial time or not). As we know, the 0-1 IP is NP-complete, but I suspect my instance can be solved in polynomial time; which of course does not contradict the hardness of th...
Can the optimization version of a problem be NP-hard while its decision version is in P?
|complexity-theory|optimization|np-complete|integer-programming|
I realized this question is a [duplicate](https://cs.stackexchange.com/questions/6138/problem-with-implementing-brzozowskis-algorithm). Basically, as @Pseudonym mentioned above, when reverting DFA you should avoid introducing new starting state of the NFA even if there were multiple finish states in DFA. Instead jus...
The assembler translates human-readable instructions to machine-language code, which are mere binary numbers. The codes are made of an opcode (identification number of a specific operation) followed by arguments (register number, memory address, immediate value). The processor fetches the opcodes one after another a...
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**Hint:** Forget about the stretch of the PRG and let's instead focus on the whether the output of $f$ necessarily looks like a random string (even if we give it a truly random string instead of a PRG output). **Answer:** The claim is false for a general OWF. A OWF is not guaranteed to have a "random looking" outpu...
I am trying to optimize a building layout in a game, and it seems like the problem could be solved by a computer much quicker than by my own trial and error. However, I only have a cursory understanding of programming (mostly JavaScript), so I'm hoping some software exists which can do most of the work for me, or some ...
Is there a good platform/software/language to make a computer analyze this optimization problem?
|graphs|optimization|
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I am trying to optimize a building layout in a game, and it seems like the problem could be solved by a computer much quicker than by my own trial and error. However, I only have a cursory understanding of programming (mostly JavaScript), so I'm hoping some software exists which can do most of the work for me, or some ...
Often, if the decision problem can be solved in polynomial time, the optimization problem can be solved in polynomial time as well. For example, if you could decide in polynomial time if a problem has a solution with at most a certain cost, you may be able to binary search for the minimal possible cost. Your decisio...
It is given that the language is not decidable. [![enter image description here][1]][1] [1]: https://i.stack.imgur.com/e1cIB.png Is this language Turing-recognizable?
EPSILON(CFG) = {<G,H> | G and H are CFGs where the concatenation is epsilon. is this language Turing-recognizable?
|undecidability|turing-recognizable|
No, this only works one way. If there is a polynomial time reduction from $A$ to $B$, then $B \in P \implies A \in P$. This works irrespective of the what kind of languages $A$ and $B$ are. The converse is not true. For example, take two languages $A, B \notin P$ such that there is *no* polynomial time reduction ...
My understanding is that this statement regarding the halting problem is proven: >Given a Turning Machine (TM) A and an input B, there does not exist any TM C which can, given A and B as input, determine in a finite number of steps whether A halts on input B for all possible A and B. What I want to know is whether ...
Does the unsolvability of the halting problem imply the existence of Turing machines which cannot be proven either to halt or not halt?
|formal-languages|turing-machines|
I am trying to optimize a building layout in a game, and it seems like the problem could be solved by a computer much quicker than by my own trial and error. However, I only have a cursory understanding of programming (mostly JavaScript), so I'm hoping some software exists which can do most of the work for me, or some ...
My understanding is that this statement regarding the halting problem is proven: >Given a Turning Machine (TM) A and an input B, there does not exist any TM C which can, given A and B as input, determine in a finite number of steps whether A halts on input B for all possible A and B. What I want to know is whether ...
Consider the language $\overline{\mathsf{EPSILON}_{\mathsf{CFG}}} = \{ <G, H> \mid \text{$G$ and $H$ are CFGs and $L(G) \cap L(H) \neq \{\varepsilon\}$} \}$. If $\overline{\mathsf{EPSILON}_{\mathsf{CFG}}}$ and $\mathsf{EPSILON}_{\mathsf{CFG}}$ were recognizable, then they would both be decidable*. Since $\mathsf{EP...
Consider the language $\overline{\mathsf{EPSILON}_{\mathsf{CFG}}} = \{ <G, H> \mid \text{$G$ and $H$ are CFGs and $L(G) \cap L(H) \neq \{\varepsilon\}$} \}$. If $\overline{\mathsf{EPSILON}_{\mathsf{CFG}}}$ and $\mathsf{EPSILON}_{\mathsf{CFG}}$ were both recognizable, then they would both be decidable*. Since $\math...
I was working on a problem for some time now, and I made a data structure to solve it. To my surprise, I could not find any instance of this data structure on the internet (though I am certain someone has thought of this). Put simply, it is a sorted linked list and a sorted array, with the array pointing to spots a ...
My understanding is that this statement regarding the halting problem is proven: >There does not exist any TM C that can, given a Turing machine A and input B as inputs, determine in a finite number of steps whether A halts on input B, and that works correctly for all A and B. What I want to know is whether this ...
That's a complex set of requirements, and I don't think I understand them all, so I'll suggest a few general approaches for this sort of problem: One standard approach is to formulate this as an instance of [integer linear programming](https://en.wikipedia.org/wiki/Integer_programming), and use an off-the-shelf ILP ...
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The usual many-one reduction involves Turing machines transforming an input, $w$, of some language to an input, $f(w)$, of some other language in polynomial time. (Where $w \in L_1 \iff f(w) \in L_2$). But for $P$-completeness, logspace or NC reductions are often used instead (taken from [wikipedia](https://en.wikip...
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Elaborating from my comments above, here is at least one partial answer to your question: As has been clearly known for about 100 years, there is no program that can correctly solve the halting problem 100% of the time, given any other program we want it to analyze. Or, at least, as Turing put it, such a program "ca...
Got inspiration while reading history book. Inspired by: [China, the cake of kings and emperors, Le Petit Journal 1898][1] **Background:** > After the Second Opium War, United Kingdom(UK), France, Russia, Germany and Japan have a meeting to dividing China the cake. The cake have fixed size but can be break d...
Data structure for represent the cake in cake diving problem?
|algorithms|data-structures|
Got inspiration while reading history book. Inspired by: [China, the cake of kings and emperors, Le Petit Journal 1898][1] **Background:** > After the Second Opium War, United Kingdom(UK), France, Russia, Germany and Japan have a meeting to dividing China the cake. The cake have fixed size but can be break d...
Data structure for represent the cake in cake dividing problem?
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When speaking about many-one Karp reductions, the definition is stated below: $$ A \leq_P B \iff \exists f \colon \: \Sigma^* \mapsto \Gamma^* \: \text{such that} \: (w \in A \iff f(w) \in B) $$ where $f$ is a polynomial time total computable function. But I think this raises a bit of an issue. I have an [on...
How do Turing machines output $f(w)$?
|complexity-theory|time-complexity|reductions|constant-time|
How do Turing machines output $f(w)$ for $O(1)$ reductions?
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I have a network of 1,000 computers that are sharing processing jobs. There are a few constraints: 1. Each computer has a maximum ratio of jobs it can perform - Can be higher than an equal share 2. Computers are not obligated to do work 3. Not all of these computers will be online at any given time 4. ...
Fault-Tolerant Distributed Work Sharing