Questions tagged [definitions]
52 questions
18
votes
11 answers
Why do logic gates behave the way they do?
I am a Software Developer but I came from a non-CS background so maybe it is a wrong question to ask, but I do not get why logic gates/boolean logic behave the way they do.
Why for example:
1 AND 1 = 1 // true AND true
1 OR 0 = 1 // true OR…
aldokkani
- 317
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7
votes
3 answers
Simple cycles of length two in an undirected graph
Pedagogical question.
Background
A cycle in a graph can be defined as a sequence of vertices $v_1,\dots,v_n$ with $v_1=v_n$ such that, for each $i \in \{1,\dots,n-1\}$, the graph has an edge $(v_i,v_{i+1})$. (One can define it differently.)
The…
usul
- 4,189
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4
votes
0 answers
Understanding the Transition points of a BST
I'm trying to understand the definition of Transition point of a BST, as given in Demaine, Erik D., et al. "Dynamic optimality-almost." SIAM Journal on Computing 37.1 (2007): 240-251
Define the transition point for [a node]
y at time i to be the…
Margaret Bloom
- 91
- 3
3
votes
2 answers
Number of leaves in complete binary tree
I got confused a bit about definitions and from reading in the different forums, does both complete binary tree (last level is not full) and perfect binary tree, number of leaves are ⌈n/2⌉ for a tree with n nodes ? If not for what binary tree is it…
miiky123
- 31
- 2
3
votes
1 answer
Are two regularity properties on hypergraphs equivalent?
Let $H=\left( E_0 ,E_1 ,E_2 , \ldots , E_d \right)$ be a $d$-dimensional full-hyper graph/complex. That is to say, if for some $i\in \left[d \right]$ the hyper-edge $e_j \in E_i$ than for any $i-1$-dimensional $e_k \subset e_j$: $e_k \in E_{i-1}$.…
Benicio Agüero
- 142
- 10
3
votes
0 answers
What is the name of visiting an array starting at first element, then last element, then second, then last but one, then third, etc
For example if I have an array
[0, 1, 2, 3, 4, ..., n]
and I want to iterate over it in an order like
[0, n, 1, n - 1, 2, n - 2, ..., n // 2]
how it can be called? Is there a general name for this?
Azat Ibrakov
- 161
- 9
2
votes
2 answers
Why does it make sense to minimize regret?
In fields such as game theory and reinforcement learning, it is standard to consider the regret-minimization strategy. I don't get the motivation for the definition.
Yes, doing your best under worst-case conditions (minimax) is an interesting…
Amit Keinan
- 171
- 5
2
votes
1 answer
Are classes $\textbf{NC}$ and uniform $\textbf{NC}$ the same?
On page 117 in Arora and Barak, the definition of class $\textbf{NC}$:
For every $d$, a language $L$ is in $\textbf{NC}^d$ if $L$ can be decided
by a family of circuits $\{C_n\}$ where $C_n$ has poly(n) size and depth $O(\log^d n)$. The class…
minh quý lê
- 625
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2
votes
1 answer
Why there is no definition of cut vertices or articulation points in directed graphs?
We know cut vertex is an important definition in undirected graph, indicating a vertex which when removed, the number of connected components would increase. And we also have an efficient algorithm for it.
However we don't have such counterpart…
27rabbit
- 68
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2
votes
2 answers
Alternate definition of recursively enumerable languages
Exercise 9.2.3(c) of the book by Hoffman, Motwani, Ullman states
In fact a definition of the RE-but-not-recursive languages is that they can be enumerated but not in numerical order
How do we show this equivalent to the following definition?…
muser
- 160
- 5
2
votes
0 answers
Regarding the definitions of time-constructible functions on Wikipedia
I am reading the Wikipedia article on time-constructible functions and got confused by its definitions, given as follows:
There are two different definitions of a time-constructible function. In the first definition, a function $f$ is called…
3nondatur
- 457
- 2
- 13
2
votes
2 answers
What defines how many lookahead a lexer has?
if a lexical grammar has multiple token which start with the same character like > >> >>= and their longest length is 3, does it have 2 character lookahead?
Or is it implementation defined. Does the number of character required to produce a fixed…
noamin
- 21
- 1
2
votes
1 answer
On the definition of Error-Correcting Codes
Let us start with the following well-known definition:
Definition 1. Let $C\subseteq A^n$ be a code over $A$ and let $t\in \Bbb Z^+$ be a positive integer. We say that the code $C$ is
$\boldsymbol t$-error correcting if nearest neighbour decoding…
Chris
- 123
- 5
2
votes
1 answer
What is the difference between Hamming Distance and Manhattan Distance for non-binary data?
What is the difference between Hamming Distance and Manhattan Distance for non-binary data (specifically I am comparing points in $\mathbb{R}^2$)? I understand Manhattan sums the absolute difference in the and x and y directions but doesnt hammming…
John D
- 123
- 4
2
votes
1 answer
Why are $L$-reductions defined the way they are?
I was reading about $L$-reductions and there was one part in the definition that I thought was interesting. I wanted to know what motivated people who came up with it to have it included in the definition.
Recall that a problem $A$ is $L$-reducible…
mursalin
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