scholarly journals Simplified group activity selection with group size constraints

2021 ◽  
Author(s):  
Andreas Darmann ◽  
Janosch Döcker ◽  
Britta Dorn ◽  
Sebastian Schneckenburger
Keyword(s):  
Computational Complexity ◽  
Simple Model ◽  
Lower Bounds ◽  
Group Activity ◽  
Core Stability ◽  
Upper And Lower Bounds ◽  
Size Constraints ◽  
Broad Variety ◽  
Special Case ◽  
Additional Constraints

AbstractSeveral real-world situations can be represented in terms of agents that have preferences over activities in which they may participate. Often, the agents can take part in at most one activity (for instance, since these take place simultaneously), and there are additional constraints on the number of agents that can participate in an activity. In such a setting, we consider the task of assigning agents to activities in a reasonable way. We introduce the simplified group activity selection problem providing a general yet simple model for a broad variety of settings, and start investigating its special case where upper and lower bounds of the groups have to be taken into account. We apply different solution concepts such as envy-freeness and core stability to our setting and provide a computational complexity study for the problem of finding such solutions.

scholarly journals On the number of excursion sets of planar Gaussian fields

2020 ◽  
Vol 178 (3-4) ◽  
pp. 655-698
Author(s):  
Dmitry Beliaev ◽  
Michael McAuley ◽  
Stephen Muirhead
Keyword(s):  
Plane Wave ◽  
Lower Bounds ◽  
Upper And Lower Bounds ◽  
Gaussian Fields ◽  
Important Special Case ◽  
Level Densities ◽  
Excursion Sets ◽  
Nodal Set ◽  
Different Types ◽  
Special Case

Abstract The Nazarov–Sodin constant describes the average number of nodal set components of smooth Gaussian fields on large scales. We generalise this to a functional describing the corresponding number of level set components for arbitrary levels. Using results from Morse theory, we express this functional as an integral over the level densities of different types of critical points, and as a result deduce the absolute continuity of the functional as the level varies. We further give upper and lower bounds showing that the functional is at least bimodal for certain isotropic fields, including the important special case of the random plane wave.

SIMULATIONS OF UNARY ONE-WAY MULTI-HEAD FINITE AUTOMATA

2014 ◽  
Vol 25 (07) ◽  
pp. 877-896 ◽  
Author(s):  
MARTIN KUTRIB ◽  
ANDREAS MALCHER ◽  
MATTHIAS WENDLANDT
Keyword(s):  
Lower Bound ◽  
Lower Bounds ◽  
Finite Automaton ◽  
Finite Automata ◽  
Upper And Lower Bounds ◽  
Unary Languages ◽  
Order Of Magnitude ◽  
Simulation Results ◽  
Special Case ◽  
Nondeterministic Finite Automaton

We investigate the descriptional complexity of deterministic one-way multi-head finite automata accepting unary languages. It is known that in this case the languages accepted are regular. Thus, we study the increase of the number of states when an n-state k-head finite automaton is simulated by a classical (one-head) deterministic or nondeterministic finite automaton. In the former case upper and lower bounds that are tight in the order of magnitude are shown. For the latter case we obtain an upper bound of O(n2k) and a lower bound of Ω(nk) states. We investigate also the costs for the conversion of one-head nondeterministic finite automata to deterministic k-head finite automata, that is, we trade nondeterminism for heads. In addition, we study how the conversion costs vary in the special case of finite and, in particular, of singleton unary lanuages. Finally, as an application of the simulation results, we show that decidability problems for unary deterministic k-head finite automata such as emptiness or equivalence are LOGSPACE-complete.

scholarly journals Complexity of Some Problems Concerning Lindenmayer Systems. (Revised version)

1979 ◽  
Vol 7 (85) ◽  
Author(s):  
Neil D. Jones ◽  
Sven Skyum
Keyword(s):  
Computational Complexity ◽  
Lower Bounds ◽  
Upper And Lower Bounds ◽  
Turing Machines ◽  
Lindenmayer Systems ◽  
L Systems

<p>We determine the computational complexity of membership, emptiness and infiniteness for several types of L systems. The L systems we consider are EDOL, EOL, EDTOL, and ETOL, with and without empty productions. For each problem and each type of system we establish both upper and lower bounds on the time or memory required for solution by Turing machines.</p><p>Revised version (first version 1978 under the title <em>Complexity of Some Problems Concerning: Lindenmayer Systems</em>)</p>

Quantum uncertainty relations of Tsallis relative $\alpha$ entropy coherence baed on MUBs

2021 ◽  
Author(s):  
ZHANG Fu Gang
Keyword(s):  
Lower Bound ◽  
Positive Integer ◽  
Lower Bounds ◽  
Upper And Lower Bounds ◽  
Mutually Unbiased Bases ◽  
Uncertainty Relations ◽  
Quantum Uncertainty ◽  
Single Qubit ◽  
Qubit System ◽  
Special Case

Abstract In this paper, we discuss quantum uncertainty relations of Tsallis relative $\alpha$ entropy coherence for a single qubit system based on three mutually unbiased bases. For $\alpha\in[\frac{1}{2},1)\cup(1,2]$, the upper and lower bounds of sums of coherence are obtained. However, the above results cannot be verified directly for any $\alpha\in(0,\frac{1}{2})$. Hence, we only consider the special case of $\alpha=\frac{1}{n+1}$, where $n$ is a positive integer, and we obtain the upper and lower bounds. By comparing the upper and lower bounds, we find that the upper bound is equal to the lower bound for the special $\alpha=\frac{1}{2}$, and the differences between the upper and the lower bounds will increase as $\alpha$ increases. Furthermore, we discuss the tendency of the sum of coherence, and find that it has the same tendency with respect to the different $\theta$ or $\varphi$, which is opposite to the uncertainty relations based on the R\'{e}nyi entropy and Tsallis entropy.

The Travelling Salesman Problem in symmetric circulant matrices with two stripes

2008 ◽  
Vol 18 (1) ◽  
pp. 165-175 ◽  
Author(s):  
IVAN GERACE ◽  
FEDERICO GRECO
Keyword(s):  
Computational Complexity ◽  
Lower Bound ◽  
Lower Bounds ◽  
Travelling Salesman Problem ◽  
Minimum Cost ◽  
Circulant Matrix ◽  
Upper And Lower Bounds ◽  
Circulant Matrices ◽  
Travelling Salesman ◽  
New Construction

The Symmetric Circulant Travelling Salesman Problem asks for the minimum cost tour in a symmetric circulant matrix. The computational complexity of this problem is not known – only upper and lower bounds have been determined. This paper provides a characterisation of the two-stripe case. Instances where the minimum cost of a tour is equal to either the upper or lower bound are recognised. A new construction providing a tour is proposed for the remaining instances, and this leads to a new upper bound that is closer than the previous one.

A Generalized Turán Problem and its Applications

2018 ◽  
Vol 2020 (11) ◽  
pp. 3417-3452 ◽  
Author(s):  
Lior Gishboliner ◽  
Asaf Shapira
Keyword(s):  
Graph Theory ◽  
Lower Bounds ◽  
Polynomial Function ◽  
Upper And Lower Bounds ◽  
Turan Problem ◽  
Turán Problem ◽  
Polynomial Bounds ◽  
Removal Lemma ◽  
Special Case

Abstract The investigation of conditions guaranteeing the appearance of cycles of certain lengths is one of the most well-studied topics in graph theory. In this paper we consider a problem of this type that asks, for fixed integers ℓ and k, how many copies of the k-cycle guarantee the appearance of an ℓ-cycle? Extending previous results of Bollobás–Gy̋ri–Li and Alon–Shikhelman, we fully resolve this problem by giving tight (or nearly tight) bounds for all values of ℓ and k. We also present a somewhat surprising application of the above mentioned estimates to the study of the graph removal lemma. Prior to this work, all bounds for removal lemmas were either polynomial or there was a tower-type gap between the best-known upper and lower bounds. We fill this gap by showing that for every super-polynomial function $f(\varepsilon )$, there is a family of graphs ${\mathcal F}$, such that the bounds for the ${\mathcal F}$ removal lemma are precisely given by $f(\varepsilon )$. We thus obtain the 1st examples of removal lemmas with tight super-polynomial bounds. A special case of this result resolves a problem of Alon and the 2nd author, while another special case partially resolves a problem of Goldreich.

Bounds for the torsional rigidity of shafts with arbitrary cross-sections containing cylindrically orthotropic fibres or coated fibres

2007 ◽  
Vol 463 (2088) ◽  
pp. 3291-3309 ◽  
Author(s):  
Tungyang Chen ◽  
Robert Lipton
Keyword(s):  
Cross Section ◽  
Lower Bounds ◽  
Cross Sections ◽  
Equilateral Triangle ◽  
Torsional Rigidity ◽  
Transverse Cross Section ◽  
Upper And Lower Bounds ◽  
Cylindrical Shaft ◽  
Cylindrically Orthotropic ◽  
Additional Constraints

In this paper we derive bounds for the torsional rigidity of a cylindrical shaft with arbitrary transverse cross-section containing a number of cylindrically orthotropic fibres or coated fibres. The exact upper and lower bounds depend on the constituent shear rigidities, the area fractions, the locations of the reinforcements as well as the geometric shape of the cross-sections. Specific bounds are derived for circular shafts, elliptical shafts and cross-sections of equilateral triangle. Simplified expressions are also deduced for reinforcements with isotropic constituents. We verify that when additional constraints between the constituent properties of the phases are fulfilled, the upper and lower bounds will coincide. In the latter case, the fibres or coated fibres become neutral under torsion and the bounds recover the previously known exact torsional rigidity.

SOME NEW RELIABILITY BOUNDS FOR SUMS OF NBUE RANDOM VARIABLES

2010 ◽  
Vol 25 (1) ◽  
pp. 83-102
Author(s):  
Steven G. From
Keyword(s):  
Lower Bounds ◽  
Random Variables ◽  
Upper And Lower Bounds ◽  
Independent Random Variables ◽  
Important Special Case ◽  
Lifetime Distributions ◽  
Survivor Function ◽  
Numerical Studies ◽  
Special Case ◽  
Better Than

In this article, we discuss some new upper and lower bounds for the survivor function of the sum of n independent random variables each of which has an NBUE (new better than used in expectation) distribution. In some cases, only the means of the random variables are assumed known. These bounds are compared to the sharp bounds given in Cheng and Lam [6], which requires both means and variances known. Although the new bounds are not sharp, they often produce better upper bounds for the survivor function in the extreme right tail of many NBUE lifetime distributions, an important special case in applications. Moreover, a lower bound exists in one case not handled by the lower bounds of Theorem 3 in Cheng and Lam [6]. Numerical studies are presented along with theoretical discussions.

scholarly journals Complexity of some Problems Concerning L Systems. (Preliminary report)

1976 ◽  
Vol 5 (67) ◽  
Author(s):  
Neil D. Jones
Keyword(s):  
Computational Complexity ◽  
Lower Bounds ◽  
Preliminary Report ◽  
Upper And Lower Bounds ◽  
Turing Machines ◽  
L Systems

We study the computational complexity of some decidable systems. The problems are membership. emptiness and finiteness; the L systems are the ED0L, E0L, EDT0L and ET0L systems. For each problem and type of system we state both upper and lower bounds on the time or memory required for solution by Turing machines. Two following papers (PB-69 and PB70) will contain detailed constructions and proofs for the upper and lower bounds.

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