Questions tagged [adversary]
8 questions
4
votes
3 answers
What is a sorting algorithm that is robust to a faulty comparison?
I want to sort a list of n items with a comparison sort. However, one of the comparisons made by the algorithm will be flipped from what it's supposed to be. Specifically, there is one pair of items for which the comparator function consistently…
chausies
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3
votes
0 answers
Approximation algorithm for minimising $x_i+y_i$ for monotonically increasing sequence $x_i$ and monotonically decreasing sequence $y_i$
Given sorted $0\leq x_1 \leq x_2 \leq ... \leq x_n$ and $y_1 \geq y_2 \geq ... \geq y_n \geq 0$ non negative integers accessible through oracles, with the additional constraints $x_{i+1}-x_i \leq 1$ and $y_i - y_{i+1} \leq 1$. Can we approximate the…
AspiringMat
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2
votes
1 answer
Coming up with an adversary strategy for a clique of maximum size
I’m having trouble coming up with a good adversary strategy for this problem:
Input: a graph G
Output: the maximum size of any clique in G
Where the algorithm asks each time, “are vertices x and y adjacent?” and it could ask about any random pair of…
user141218
2
votes
2 answers
Having a better complexity / adversary argument for finding if a finite automata accepts a palindrome
Let $A$ be a DFA over a finite alphabet $ \Sigma$. Find an algorithm that indicates if $A$ accepts a palindrome and give the complexity of this algorithm.
Here is my solution:
If we denote $^t A$ the transpose of the finite automaton then in…
dzhqjk
- 63
- 5
1
vote
1 answer
lower bound proof with adversary argument
We have to run a song on a Walkman, for that we need 2 full batteries. Let's say we have a mixed set of 30 batteries (15 are empty and and 15 are full) and then only way to test if the battery is full or empty is to put them in the Walkman and try…
Mohbenay
- 319
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1
vote
0 answers
Adversary argument and proving a lower bound of an algorithm. How does it work?
I need to understand how adversary argument works to prove the lower bound of an algorithm. For now, I am looking to prove that a "certain" algorithm that takes in input array requires omega(n) comparisons. Basically it needs to compare the ith…
Osama Naeem
- 111
- 1
1
vote
0 answers
Hardness result for online matching
Currently studying the following paper:
"Fair Allocation in Online Markets" - Gollapudi and Panigrahi 2014
In which they present Theorem 2 as a hardness result for online maxmin matchings (without proof). My thinking for a counterexample which…
user143196
- 11
- 2
0
votes
0 answers
Looking for references for real-world scenarios of data-poisoning attack on labels while doing supervised learning
Consider the following mathematical model of training a neural net : Suppose $f_{w} : \mathbb{R}^n \rightarrow \mathbb{R}$ is a neural net whose weights are $w$. Suppose during the training the adversary is sampling $x \sim {\cal D}$ from some…
gradstudent
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