Knowledge (XXG)

Picking sequence

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Brams and Kaplan study the problem of allocating cabinet ministries among parties. There is a coalition of parties; each party has a different number of seats in the parliament; larger parties should be allocated more ministries or more prestigious ministries. This is a special case of
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in the following sense: an agent is always better-off if one or more of his positions in the sequence are improved (e.g, Alice is better-off in the sequence ABBA than in BABA). Both properties are still true with three or more agents, as long as they make truthful
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with different entitlements. A possible solution to this problem is to determine a picking sequence, based on the different entitlements, and let each party pick a ministry in turn. Such a solution is used in Northern Ireland, Denmark and the European parliament.
211:) if, at each point, he picks his best item. If agents have complete information on each other's preferences (as is common among parties), it may not be rational for them to choose truthfully; it may be better for them to make 49:
ABBA - Alice picks one item, then Bob picks two items, then Alice receives the remaining item. This is intuitively even more "fair" than ABAB, since, in ABAB, Bob is always behind of Alice, while ABBA is more
297:- the fractional number of items each agent is entitled to. This is the entitlement divided by the divisor (e.g, for an agent with an entitlement of 10 out of 201, the quota is 10*15/201 ~ 0.75 items). 513:
O'Leary, Brendan; Grofman, Bernard; Elklit, Jorgen (2005). "Divisor Methods for Sequential Portfolio Allocation in Multi-Party Executive Bodies: Evidence from Northern Ireland and Denmark".
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With three or more agents who make strategic choices, a picking-sequence might lead to inefficient allocations (i.e, the subgame-perfect equilibrium might not be Pareto-efficient).
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Privacy: the agents do not have to reveal their entire valuation function or even their entire ranking. They only have to reveal what item is the best for them in each step.
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agents. One way to allocate the items is to let one agent select a single item, then let another agent select a single item, and so on. A picking-sequence is a sequence of
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on bundles of items. This means that, at each point in the picking sequence, there is a single remaining item which is the "best item" for the agent. An agent is called
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ABAB - Alice picks one item, then Bob picks one item, then Alice again, then Bob again. This is more "fair" than AABB since it lets Bob more chance to get a better item.
290:- the sum of the entitlements divided by the number of items (e.g, if the sum of all entitlements is 201, and there are 15 items to share, then the divisor is 201/15). 333:
Schoolyard games often need to select "teams". When using the "ABBA" selection, the "A" team will declare "first pick" and the B team will declare "Second-Two":
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that maps the rankings to monetary values (e.g, for each agent, his best item is worth for him x dollars, his second-best item is worth for him y dollars, etc).
257:- picking items truthfully is a dominant strategy. Therefore, there exists a subgame-perfect equilibrium which is Pareto optimal, and the game is monotonic. 334: 63:
Simplicity: it is very easy for the agents to understand how the protocol works and what they should do in each step - just pick the best item.
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scoring function, and each ranking is equally probable, the "round robin" sequence (ABABAB...) attains the maximal expected sum-of-utilities.
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The allocator does not know the rankings of the agents, but he knows that all rankings are random draws from a given
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How should the picking sequence be selected? Bouveret and Lang study this question under the following assumptions:
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Picking sequences can be used to find allocations that satisfy a strong fairness and efficiency condition called
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Sylvain Bouveret and Yann Chevaleyre and Nicolas Maudet, "Fair Allocation of Indivisible Goods". Chapter 12 in:
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As an example, suppose 4 items have to be divided between Alice and Bob. Some possible picking sequences are:
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welfare (sum of utilities) or the expected egalitarian welfare (minimum utility) in various settings.
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Given the agents' different rights, what would be a fair picking sequence? Brams suggests to use
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protocol is a special case of a picking sequence in which the sequence is cyclic: 1, 2, ...,
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Brandt, Felix; Conitzer, Vincent; Endriss, Ulle; Lang, Jérôme; Procaccia, Ariel D. (2016).
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For two agents, there exists a simple modification of the picking-sequence which is a
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agent-names, where each name determines what agent is the next to pick an item.
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Mathematics and Democracy: Designing Better Voting and Fair-Division Procedures
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The agents may have different rankings on the items, but there is a common
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Brams assumes that each agent has a strict ordering on the items, and has
550:"Competitive equilibrium for almost all incomes: existence and fairness" 246:
With three or more agents who make strategic choices, the game might be
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Brams, Steven J.; Kaplan, Todd R. (2004). "Dividing the Indivisible".
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AABB - Alice picks two items, then Bob picks the two remaining items.
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A general elicitation-free protocol for allocating indivisible goods
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A picking-sequence has several merits as a fair division protocol:
250:, i.e, an agent might do worse by picking earlier in the sequence. 274:. The two most commonly used methods are the ones proposed by 355:' The Win-Win Solution: Guaranteeing Fair Shares to Everybody 231:
With two agents, both truthful and strategic choices lead to
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Kalinowski et al show that, when there are two agents with a
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A social welfare optimal sequential allocation procedure
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They show picking-sequences that maximize the expected
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reports, each of which includes a number between 1 and
87: 113: 219:) choices. Thus, the picking sequence induces a 454:. Princeton, NJ: Princeton University Press. 353:Steven Brams and Alan D. Taylor (1999–2000). 159:The goal of the allocator is to maximize the 8: 272:apportionment of congress seats among states 366: 364: 138:function (this implies that the items are 565: 554:Autonomous Agents and Multi-Agent Systems 489: 103: 86: 375:Handbook of Computational Social Choice 345: 282:. Both methods start in the same way: 515:American Journal of Political Science 444: 442: 440: 415:10.5591/978-1-57735-516-8/ijcai11-024 223:and it is interesting to analyze its 7: 335:List of traditional children's games 186:Fairness with different entitlements 235:allocations. Moreover, the game is 114:{\displaystyle \Theta (m\log {m})} 88: 81:, so that the total complexity is 14: 548:Segal-Halevi, Erel (2020-02-20). 527:10.1111/j.0092-5853.2005.00118.x 262:Determining the picking-sequence 470:Journal of Theoretical Politics 270:, similar to the ones used for 28:items have to be divided among 378:. Cambridge University Press. 227:. Several results are proved: 108: 91: 1: 320:round-robin item allocation 225:subgame-perfect equilibrium 628: 576:10.1007/s10458-020-09444-z 357:. New York: W. W. Norton. 482:10.1177/0951629804041118 450:Steven J. Brams (2008). 154:probability distribution 71:communication complexity 612:Fair division protocols 308:competitive equilibrium 302:Competitive equilibrium 165:social welfare function 201:responsive preferences 115: 116: 193:fair item assignment 126:Welfare maximization 85: 22:fair item assignment 392:free online version 73:: it requires only 255:truthful mechanism 134:Each agent has an 111: 20:is a protocol for 140:independent goods 619: 596: 595: 569: 545: 539: 538: 510: 504: 503: 493: 465: 446: 435: 434: 433:. AAAI-13. 2013. 425: 419: 418: 401: 395: 389: 368: 359: 358: 350: 280:Thomas Jefferson 233:Pareto efficient 147:scoring function 136:additive utility 120: 118: 117: 112: 107: 18:picking sequence 627: 626: 622: 621: 620: 618: 617: 616: 602: 601: 600: 599: 547: 546: 542: 512: 511: 507: 467: 466:. Adapted from 462: 449: 447: 438: 427: 426: 422: 403: 402: 398: 386: 371: 369: 362: 352: 351: 347: 342: 316: 304: 268:divisor methods 264: 221:sequential game 188: 128: 83: 82: 57: 12: 11: 5: 625: 623: 615: 614: 604: 603: 598: 597: 540: 505: 460: 436: 420: 396: 384: 360: 344: 343: 341: 338: 315: 312: 303: 300: 299: 298: 293:Calculate the 291: 286:Calculate the 276:Daniel Webster 263: 260: 259: 258: 251: 244: 241: 187: 184: 169: 168: 161:expected value 157: 150: 143: 127: 124: 123: 122: 110: 106: 102: 99: 96: 93: 90: 67: 64: 56: 53: 52: 51: 47: 44: 13: 10: 9: 6: 4: 3: 2: 624: 613: 610: 609: 607: 593: 589: 585: 581: 577: 573: 568: 563: 559: 555: 551: 544: 541: 536: 532: 528: 524: 520: 516: 509: 506: 501: 497: 492: 487: 483: 479: 475: 471: 463: 461:9780691133218 457: 453: 448:Chapter 9 in 445: 443: 441: 437: 432: 431: 424: 421: 416: 412: 408: 407: 400: 397: 393: 387: 385:9781107060432 381: 377: 376: 367: 365: 361: 356: 349: 346: 339: 337: 336: 331: 329: 326:, 1, 2, ..., 325: 321: 313: 311: 309: 301: 296: 292: 289: 285: 284: 283: 281: 277: 273: 269: 261: 256: 252: 249: 248:non-monotonic 245: 242: 238: 234: 230: 229: 228: 226: 222: 218: 214: 213:sophisticated 210: 206: 202: 197: 194: 185: 183: 181: 176: 174: 166: 162: 158: 155: 151: 148: 144: 141: 137: 133: 132: 131: 125: 104: 100: 97: 94: 80: 76: 72: 68: 65: 62: 61: 60: 54: 48: 45: 42: 41: 40: 37: 35: 31: 27: 23: 19: 557: 553: 543: 518: 514: 508: 473: 469: 451: 429: 423: 405: 399: 374: 354: 348: 332: 327: 323: 317: 305: 294: 287: 267: 265: 247: 236: 216: 212: 208: 204: 198: 189: 177: 170: 146: 129: 78: 74: 58: 38: 33: 29: 25: 17: 15: 521:: 198–211. 491:10036/26974 173:utilitarian 567:1705.04212 476:(2): 143. 340:References 55:Advantages 24:. Suppose 592:254232282 584:1573-7454 560:(1): 26. 500:154854134 237:monotonic 217:strategic 101:⁡ 89:Θ 50:balanced. 606:Category 314:See also 240:choices. 209:truthful 163:of some 288:divisor 205:sincere 590:  582:  535:547519 533:  498:  458:  382:  330:, ... 588:S2CID 562:arXiv 531:S2CID 496:S2CID 295:quota 180:Borda 580:ISSN 456:ISBN 380:ISBN 318:The 278:and 69:Low 572:doi 523:doi 486:hdl 478:doi 411:doi 98:log 608:: 586:. 578:. 570:. 558:34 556:. 552:. 529:. 519:49 517:. 494:. 484:. 474:16 472:. 439:^ 409:. 363:^ 310:. 142:). 16:A 594:. 574:: 564:: 537:. 525:: 502:. 488:: 480:: 464:. 417:. 413:: 394:) 390:( 388:. 328:n 324:n 215:( 207:( 167:. 156:. 121:. 109:) 105:m 95:m 92:( 79:m 75:m 34:m 30:n 26:m

Index

fair item assignment
communication complexity
additive utility
independent goods
probability distribution
expected value
social welfare function
utilitarian
Borda
fair item assignment
responsive preferences
sequential game
subgame-perfect equilibrium
Pareto efficient
truthful mechanism
apportionment of congress seats among states
Daniel Webster
Thomas Jefferson
competitive equilibrium
round-robin item allocation
List of traditional children's games


Handbook of Computational Social Choice
ISBN
9781107060432
free online version
A general elicitation-free protocol for allocating indivisible goods
doi
10.5591/978-1-57735-516-8/ijcai11-024

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