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1.
Peter C. Fishburn 《Social Choice and Welfare》2002,19(2):431-447
Let f(n) be the maximum cardinality of an acyclic set of linear orders on {1, 2, … , n}. It is known that f(3)=4, f(4)=9, f(5)=20, and that all maximum-cardinality acyclic sets for n≤ 5 are constructed by an “alternating scheme”. We outline a proof that this scheme is optimal for n=6, where f (6)=45. It is known for large n that f (n) >(2.17)n and that no maximum-cardinality acyclic set conforms to the alternating scheme. Ran Raz recently proved that f (n)<c
n for some c>0 and all n. We conjecture that f (n + m)≤f (n + 1) f (m + 1) for n , m≥ 1, which would imply f (n)<(2.591)n − 2 for all large n.
Received: 12 April 2000/Accepted: 4 December 2000 相似文献
2.
Peter Fishburn 《Social Choice and Welfare》1992,9(3):259-262
Craven's conjecture says that 2
n–1 is the maximum number of linear orders on {1, 2,...n} that simultaneously satisfy certain restrictions on three-element subsets of {1, 2,...n}. This is true for n=3, but the maximum exceeds 2
n–1 for n4. There is a set of nine linear orders on {1, 2, 3, 4} that satisfy the restrictions. As n gets large, the ratio of the size of the maximum satisfying set to 2
n–1 approaches infinity. 相似文献
3.
Norman Schofield 《Social Choice and Welfare》1998,15(2):161-185
Suppose p is a smooth preference profile (for a society, N) belonging to a domain P
N
. Let σ be a voting rule, and σ(p)(x) be the set of alternatives in the space, W, which is preferred to x. The equilibrium E(σ(p)) is the set {x∈W:σ(p)(x) is empty}. A sufficient condition for existence of E(σ(p)) when p is convex is that a “dual”, or generalized gradient, dσ(p)(x), is non-empty at all x. Under certain conditions the dual “field”, dσ(p), admits a “social gradient field”Γ(p). Γ is called an “aggregator” on the domain P
N
if Γ is continuous for all p in P
N
. It is shown here that the “minmax” voting rule, σ, admits an aggregator when P
N
is the set of smooth, convex preference profiles (on a compact, convex topological vector space, W) and P
N
is endowed with a C
1-topology. An aggregator can also be constructed on a domain of smooth, non-convex preferences when W is the compact interval. The construction of an aggregator for a general political economy is also discussed. Some remarks
are addressed to the relationship between these results and the Chichilnisky-Heal theorem on the non-existence of a preference
aggregator when P
N
is not contractible.
Received: 4 July 1995 / Accepted: 26 August 1996 相似文献
4.
Peter C. Fishburn 《Social Choice and Welfare》2005,24(2):199-210
A set T of linear orders of [n] = {1,2, . . . ,n} is subcyclic if every 3-set in [n] has one order that appears in no order in T. With g(n) the maximum cardinality of a subcyclic set for n, Raz [8] proved that g(n)<cn for some c>0, thus resolving a longstanding conjecture of a similar upper bound for maximum acyclic sets. The present paper proves that g(4)=14 and g(5)=42 with both maxima attained only by subcyclic sets with a particular structure for all quadruples in [n]. We conjecture a similar result for larger n, in which case g(n) is the nth Catalan number and min(c)=4 for Raz’s bound. 相似文献
5.
Luc Lauwers 《Social Choice and Welfare》1997,14(2):319-332
The literature on infinite Chichilnisky rules considers two forms of anonymity: a weak and a strong. This note introduces
a third form: bounded anonymity. It allows us to prove an infinite analogue of the “Chichilnisky– Heal-resolution” close to
the original theorem: a compact parafinite CW-complex X admits a bounded anonymous infinite rule if and only if X is contractible.
Furthermore, bounded anonymity is shown to be compatible with the finite and the [0, 1]-continuum version of anonymity and
allows the construction of convex means in infinite populations. With X=[0, 1], the set of linear bounded anonymous rules coincides with the set of medial limits.
Received: 30 October 1993/Accepted: 22 April 1996 相似文献
6.
The inverse Banzhaf problem 总被引:1,自引:1,他引:0
Let ${\mathcal{F}}Let F{\mathcal{F}} be a family of subsets of the ground set [n] = {1, 2, . . . , n}. For each i ? [n]{i \in [n]} we let p(F,i){p(\mathcal{F},i)} be the number of pairs of subsets that differ in the element i and exactly one of them is in F{\mathcal{F}}. We interpret p(F,i){p(\mathcal{F},i)} as the influence of that element. The normalized Banzhaf vector of F{\mathcal{F}}, denoted B(F){B(\mathcal{F})}, is the vector (B(F,1),...,B(F,n)){(B(\mathcal{F},1),\dots,B(\mathcal{F},n))}, where
B(F,i)=\fracp(F,i)p(F){B(\mathcal{F},i)=\frac{p(\mathcal{F},i)}{p(\mathcal{F})}} and p(F){p(\mathcal{F})} is the sum of all p(F,i){p(\mathcal{F},i)}. The Banzhaf vector has been studied in the context of measuring voting power in voting games as well as in Boolean circuit
theory. In this paper we investigate which non-negative vectors of sum 1 can be closely approximated by Banzhaf vectors of
simple voting games. In particular, we show that if a vector has most of its weight concentrated in k < n coordinates, then it must be essentially the Banzhaf vector of some simple voting game with n − k dummy voters. 相似文献
7.
Acyclic sets of linear orders via the Bruhat orders 总被引:1,自引:1,他引:0
We describe Abello’s acyclic sets of linear orders [SIAM J Discr Math 4(1):1–16, 1991] as the permutations visited by commuting
equivalence classes of maximal reduced decompositions. This allows us to strengthen Abello’s structural result: we show that
acyclic sets arising from this construction are distributive sublattices of the weak Bruhat order. This, in turn, shows that
Abello’s acyclic sets are, in fact, the same as Chameni-Nembua’s distributive covering sublattices (S.T.D.C s). Fishburn’s alternating scheme is shown to be a special case of the Abello/Chameni-Nembua acyclic sets. Any acyclic set that arises in this way can be represented
by an arrangement of pseudolines, and we use this representation to derive a simple closed form for the cardinality of the
alternating scheme. The higher Bruhat orders prove to be a natural mathematical framework for this approach to the acyclic
sets problem.
We would like to thank the Editor, Professor Bernard Monjardet, and two anonymous referees for their comments and additional
references. 相似文献
8.
Norman Schofield 《Social Choice and Welfare》1999,16(3):445-470
This paper defines a fine C
1-topology for smooth preferences on a “policy space”, W, and shows that the set of convex preference profiles contains open sets in this topology.
It follows that if the dimension(W)≤v(?)−2 (where v(?) is the Nakamura number of the voting rule, ?), then the core of ? cannot be generically empty. For higher dimensions,
an “extension” of the voting core, called the heart of ?, is proposed. The heart is a generalization of the “uncovered set”.
It is shown to be non-empty and closed in general. On the C
1-space of convex preference profiles, the heart is Paretian. Moreover, the heart correspondence is lower hemi-continuous and
admits a continuous selection. Thus the heart converges to the core when the latter exists. Using this, an aggregator, compatible
with ?, can be defined and shown to be continuous on the C
1-space of smooth convex preference profiles.
Received: 3 April 1995/Accepted: 8 April 1998 相似文献
9.
Ralph W. Bailey 《Social Choice and Welfare》1998,15(4):559-562
The number of Arrovian constitutions, when N agents are to rank n alternatives, is p(n)
p(n)
N
, where p(n) is the number of weak orderings of n alternatives. For n≤15, p(n) is the nearest integer to n!/2(log2)
n
+1, the dominant term of a series derived by contour integration of the generating function. For large n, about n/17 additional terms in the series suffice to compute p(n) exactly.
Received: 29 May 1995 / Accepted: 22 May 1997 相似文献
10.
Ehud Goldhammer Yelena Rivlin Sergei Shnizer Allah Shanati Moran Sagiv Uri Rosenschein 《European review of aging and physical activity》2010,7(1):37-41
The purpose of this paper is to find out whether serum oxidizability potential measured before an exercise test (EXT) correlates
with age and ischemic heart disease severity. Oxidizability potential was determined in 3 age groups, in gr. I patients < 45 years,
in gr. II age range = 45 - 70years {\hbox{range}} = {45} - {7}0{\hbox{years}} , and in gr. III patients > 70 years. Included subjects had chronic ischemic heart disease (IHD) and underwent a symptom-limited
EXT upon initiation of a cardiac rehabilitation program. The thermo-chemiluminescence (TCL) assay was used to assess serum
oxidizability potential. This assay is based on heat-induced oxidation of serum, leading to the formation of electronically
excited species in the form of unstable carbonyls, which further decompose into stable carbonyls and light energy (low chemiluminescence).
Measured photons emission is represented by a kinetic curve which is described by its amplitude and slope (=ratio). We assessed
the correlations of TCL ratio with age, exercise duration, metabolic equivalents (METS), maximal heart rate (mHR), maximal
systolic BP, >1 mm S-T depression, diabetes, hypertension, smoking, left ventricular ejection fraction (LVEF)> or <40%, previous
myocardial infarction, and aorto-coronary bypass surgery. A high TCL ratio (%) correlated well with METS (r = 0.82), mHR (r = 0.77) and with exercise-induced S-T segment shift (r = 0.86, p < 0.05). A lower serum oxidizability potential, expressed as a low TCL ratio, thus suggestive of a previous high oxidative
stress, was found in the two older age groups compared to gr. I (<45 years), p = 0.041, and in particular, in gr. III patients with low LVEF%. The TCL ratio (%) in gr. III was 188.7 ± 14.5, 192 ± 17 in
gr. II, and 214 ± 13 in gr. I (p < 0.05), and was 166 ± 13.1 in gr. III with LVEF < 45% as compared to 271 ± 15.7 in gr. I patients with LVEF > 45% (p < 0.01). A trend for lower TCL ratio (%) was found in diabetic, hypertensive, and post-coronary bypass surgery patients.
A paradoxically low TCL ratio (low oxidizability potential) was observed in patients without S-T depression compared to patients
with S-T depression (189 ± 22 vs. 201 ± 15, p = NS), due to the fact these patients had a much lower LVEF% and a lower exercise capacity. Serum oxidizability potential
is associated with age, EXT parameters, results, and IHD severity. TCL ratio is an “easy-to-measure marker” that might be
incorporated into risk assessment and prediction in aged IHD patients. 相似文献
11.
Edward M. Bolger 《Social Choice and Welfare》2002,19(4):709-721
In the first three sections of this paper we present a set of axioms which provide a characterization of an extension of
the Banzhaf index to voting games with r alternatives, such as the United Nations Security Council where a nation can vote “yes”, “no”, or “abstain”. The fourth section
presents a set of axioms which characterizes a power index based on winning sets instead of pivot sets.
Received: 4 April 2000/Accepted: 30 April 2001 相似文献
12.
N. Will Shead David C. Hodgins 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》2009,25(3):357-375
Factor scores on a gambling expectancy questionnaire (GEQ) were used to subtype 132 university students who gamble regularly
(37.9% male; M age = 22.6 years, SD = 6.04) as: Reward Expectancy Gamblers (Reward EGs)—have strong expectations that gambling
augments positive mood, Relief Expectancy Gamblers (Relief EGs)—have strong expectations that gambling relieves negative affect,
and Non-Expectancy Gamblers (Non-EGs)—have neither strong expectation. Gambling on a high-low card game was compared across
subtypes following priming for either “relief” or “reward” affect-regulation expectancies with the Scrambled Sentence Test
(SST). The hypothesized Prime type × GEQ subtype interaction was not significant. When a more stringent set of criteria for
GEQ subtyping was imposed, the “purified” sub-sample (n = 54) resulted in the hypothesized statistically significant Prime type × GEQ subtype interaction. Relief EGs gambled more
after being primed with the construct “relief of negative emotions” compared to after being primed with the construct “augmentation
of positive emotion.” Planned orthogonal contrasts showed a significant linear increase in number of bets made across GEQ
subtypes when prime type corresponded to GEQ subtype. The results suggest a need for components in gambling treatment programs
that address clients’ expectancies that gambling can provide a specific desirable emotional outcome. 相似文献
13.
The purpose of the paper is to provide a general framework for analyzing “preference for opportunities.” Based on two simple
axioms a fundamental result due to Kreps is used in order to represent rankings of opportunity sets in terms of multiple preferences.
The paper provides several refinements of the basic representation theorem. In particular, a condition of “closedness under
compromise” is suggested in order to distinguish the flexibility interpretation of the model from normative interpretations which play a crucial role in justifying the intrinsic value of opportunities. Moreover, the paper clarifies the link between the multiple preference approach and the “choice function”
approach to evaluating opportunities. In particular, it is shown how the well-known Aizerman/Malishevski result on rationalizability
of choice functions can be obtained as a corollary from the more general multiple preference representation of a ranking of
opportunity sets.
Received: 3 September 1996 / Accepted: 18 August 1997 相似文献
14.
The majoritarian compromise is majoritarian-optimal and subgame-perfect implementable 总被引:2,自引:0,他引:2
It is shown that the Majoritarian Compromise of Sertel (1986) is subgame-perfect implementable on the domain of strict preference profiles, although it fails to be Maskin-monotonic and is hence not implementable in Nash
equilibrium. The Majoritarian Compromise is Pareto-optimal and obeys SNIP (strong no imposition power), i.e. never chooses a strict majority's worst candidate. In fact, it is “majoritarian approving”
i.e. it always picks “what's good for a majority” (alternatives which some majority regards as among the better “effective”
half of the available alternatives). Thus, being Pareto-optimal and majoritarian approving, it is majoritarian-optimal. Finally, the Majoritarian Compromise is measured against various criteria, such as consistency and Condorcet-consistency.
Received: 31 January 1995/Accepted: 22 July 1998 相似文献
15.
Define the predictability number α(T) of a tournament T to be the largest supermajority threshold for which T could represent the pairwise voting outcomes from some population of voter preference orders. We establish that the predictability
number always exists and is rational. Only acyclic tournaments have predictability 1; the Condorcet voting paradox tournament
has predictability ; Gilboa has found a tournament on 54 alternatives (i.e. vertices) that has predictability less than , and has asked whether a smaller such tournament exists. We exhibit an 8-vertex tournament that has predictability , and prove that it is the smallest tournament with predictability < . Our methodology is to formulate the problem as a finite set of two-person zero-sum games, employ the minimax duality and
linear programming basic solution theorems, and solve using rational arithmetic.
D. Shepardson was supported by a NSF Graduate Research Fellowship during the course of this work. 相似文献
16.
Bertrand Tchantcho Lawrence Diffo Lambo Roland Pongou Joël Moulen 《Social Choice and Welfare》2010,34(3):379-396
We study the core of “(j, k) simple games”, where voters choose one level of approval from among j possible levels, partitioning the society into j coalitions, and each possible partition facing k levels of approval in the output (Freixas and Zwicker in Soc Choice Welf 21:399–431, 2003). We consider the case of (j, 2) simple games, including voting games in which each voter may cast a “yes” or “no” vote, or abstain (j = 3). A necessary and sufficient condition for the non-emptiness of the core of such games is provided, with an important
application to weighted symmetric (j, 2) simple games. These results generalize the literature, and provide a characterization of constitutions under which a
society would allow a given number of candidates to compete for leadership without running the risk of political instability.
We apply these results to well-known voting systems and social choice institutions including the relative majority rule, the
two-thirds relative majority rule, the United States Senate, and the United Nations Security Council. 相似文献
17.
Correlates of sport participation among community-dwelling elderly people in Germany: a cross-sectional study 总被引:1,自引:1,他引:0
Timo Hinrichs Ulrike Trampisch Ina Burghaus Heinz G. Endres Renate Klaaßen-Mielke Anna Moschny Petra Platen 《European review of aging and physical activity》2010,7(2):105-115
The aims of this study were (1) to analyze the sport participation in a cohort of community-dwelling elderly people in Germany
and (2) to evaluate associations between sport participation, sociodemographic factors, cardiovascular risk factors, and health
status. In a monitored prospective cohort study (getABI), 6,880 unselected patients ≥65 years have been followed up by 344
general practitioners beginning in 2001. As part of the 5-year follow-up telephone interview, a sample of 1,376 participants
was interviewed on sport participation. The association between participation in at least one sporting activity (“sporty”
yes/no) during the past week (cycling) or month (other sports) and the following parameters was analyzed by logistic regression:
age, sex, immigration background, education, waist circumference, smoking, self-reported health, history of vascular events,
diabetes mellitus, lipometabolic disorder, and arterial hypertension. Analysis of activities (n = 1,304; median age 76 (70–94) years; 55.1% women) showed that 27.6% of participants rode a bicycle during the previous week.
During the previous month, 24.9% of participants did gymnastics or strength training, and 16.5% swam. Of all participants,
53.8% were sporty. Multivariate analysis revealed several independent factors to be associated with being sporty (p < 0.05): younger age, male sex, higher education, nonsmoking, better self-reported health, and not being diagnosed with diabetes.
Immigration background, waist circumference, history of vascular events, lipometabolic disorder, and hypertension did not
show a statistically significant association (p ≥ 0.05) with sport participation. Summing up, the most frequently performed sporting activities were cycling, gymnastics
or strength training, and swimming. Sport participation was associated with, for example, age and sex. 相似文献
18.
This paper characterizes strategy-proof social choice functions (SCFs), the outcome of which are multiple public goods. Feasible
alternatives belong to subsets of a product set . The SCFs are not necessarily “onto”, but the weaker requirement, that every element in each category of public goods A
k
is attained at some preference profile, is imposed instead. Admissible preferences are arbitrary rankings of the goods in
the various categories, while a separability restriction concerning preferences among the various categories is assumed. It
is found that the range of the SCF is uniquely decomposed into a product set in general coarser than the original product set, and that the SCF must be dictatorial on each component B
l
. If the range cannot be decomposed, a form of the Gibbard–Satterthwaite theorem with a restricted preference domain is obtained. 相似文献
19.
James Schummer 《Social Choice and Welfare》1996,14(1):47-56
Strategy-proofness has been shown to be a strong property, particularly on large domains of preferences. We therefore examine the existence
of strategy-proof and efficient solutions on restricted, 2-person domains of exchange economies. On the class of 2-person exchange economies in which agents
have homothetic, strictly convex preferences we show, as Zhou (1991) did for a larger domain, that such a solution is necessarily
dictatorial. As this proof requires preferences exhibiting high degrees of complementarity, our search continues to a class of linear
preferences. Even on this “small” domain, the same negative result holds. These two results are extended to many superdomains,
including Zhou’s.
Received: 9 June 1995/Accepted: 8 January 1996 相似文献
20.
Christena Nippert-Eng 《Sociological Forum》1996,11(3):563-582
This article presents a discussion of the relationship between classification systems and individuals' everyday activities.
The concept of “boundary work” is defined as the practices that concretize and give meaning to mental frameworks by placing,
maintaining, and challenging cultural categories. “Home” and “work” provide a case study for examining boundary work across
a range of realm relationships, from those that are highly “integrating” to those that are highly “segmenting.” Boundary practices
involving calendars and keys, clothes and appearances, eating and drinking, money, people and their representations (like
photographs and gifts), talk styles and conversations, reading materials and habits, and work breaks (including lunches and
vacations) are discussed. Mary Douglas's work on categorical purity helps illustrate the relationship between cognitive order
and visible behavior seen in the boundary work of home and work.
This article includes material that was published in a larger study,Home and Work: Negotiating Boundaries Through Everyday Life (1996 University of Chicago Press), after it was presented at the 1995 Eastern Sociological Society meetings in Philadelphia. 相似文献