d4-conf-aaai-2021-0803

· ? (d4-conf-aaai-2021-0803)

no mirror
paperd4-conf-aaai-2021-0803
authors—
venue?
filed underunclassified
judged bygpt-6-luna / xhigh (triple__luna__xhigh__c6r1)
judge confidencehigh
authors would recognise ityes

Why no mirror

Theorems 1–4 establish geometric bounds on β*, without stating an algorithm, running-time guarantee, or hardness result. The proponent correctly notes that the EPTAS belongs to prior work and does not offer any of this paper’s theorems as a computational anchor. Weighted feasibility is a coherent continuous-population question, but it cannot supply the missing computational result from this paper.

fails bit a — no named computational result to mirror

What the mirror covers

The proposed weighted feasibility question concerns the paper’s instance-level β-plurality objective; it does not compute the global β* bounds, and the paper’s geometric theorems do not provide computational results.

Open questions for a prover

The case FOR (proponent)

The strongest positive case is a weighted spatial electorate. A type is a location \(x\) in a fixed Euclidean space: voters at the same location have the same distance preferences over every possible choice. The mass \(\mu_x\) is that type’s share of the population. This fits a plausible regime such as a large campus or town where many residents are modeled at each of a relatively small number \(\tau\) of residential sites, even though the total population \(n\) is much larger.

A precise mirror is Weighted \(\beta\)-Plurality Feasibility. The input is a fixed dimension \(d\), rational points \(x_1,\ldots,x_\tau\in\mathbb Q^d\), positive binary-rational masses \(w_i\) summing to \(1\), and a rational threshold \(b\in(0,1]\). The question is whether there is a choice \(p\in\mathbb R^d\) such that, for every alternative \(q\in\mathbb R^d\), \(\sum_{i:\,b\lVert p-x_i\rVert_2\le \lVert q-x_i\rVert_2}w_i\ge \tfrac12\). A yes-solution is such a \(p\); a no-solution certifies that none exists. Optimizing the largest feasible \(b\) gives the paper’s instance-level objective. This preserves the authors’ majority condition and distance model; replacing voter counts by population fractions is a direct high-multiplicity analogue.

There is a serious limitation to the positive case: the paper has no qualifying named computational anchor under your criteria. Theorem 1 proves \(\beta^*_{(X,d)}\ge\sqrt2-1\) for every metric space; Theorem 2 gives a metric space with \(\beta^*_{(X,d)}=\tfrac12\); Theorem 3 proves an upper bound of \(\tfrac12\) for continuous graph metrics containing a cycle; and Theorem 4 proves a lower bound of about \(0.557\) for Euclidean spaces in arbitrary dimension. These are mathematical bounds, not statements that a problem is in P, NP-hard, or otherwise computationally classified. The EPTAS mentioned in the paper is attributed to Aronov et al. and is not a numbered result of this paper. So I cannot honestly present any of these as an anchor of the required kind.

As a provisional computational question, I would tentatively expect approximation in fixed dimension to be tractable: the paper reports an EPTAS for the unweighted finite-voter instance from prior work, making a weighted extension a reasonable target. That is a conjecture about the mirror, not a result established here; exact weighted feasibility remains unclassified. Further questions include whether the bounds extend to atomless population distributions and how the weighted problem’s complexity depends on \(d,\tau\), and the input bit length.

The weakest point is that this paper studies geometric existence bounds, while its voters remain a finite multiset; its continuous space is principally the space of voter locations and choices, not a continuous population. Its extremal examples also use very small voter supports, so they do not themselves show that large populations with few types gain computationally. The mirror is recognizable and precise, but the paper supplies no named complexity result to anchor it.

The case AGAINST (opponent, writing after the proponent)

The paper has no named computational result to anchor a ChoCo mirror. Theorems 1–4 establish geometric bounds on \(\beta^*\): a universal lower bound, a metric-space example, a bound for continuous graph metrics, and a Euclidean lower bound. None classifies an algorithmic problem or gives a complexity result. Theorem 3’s “continuous” graph metric concerns the metric space; its voters are still a finite multiset. The EPTAS mentioned in the introduction belongs to Aronov et al.’s prior work, so it cannot supply this paper’s missing anchor.

Weighted \(\beta\)-Plurality Feasibility is a coherent model: agents at the same location have identical distance preferences, and rational masses represent their population shares. Optimizing \(\beta\) or deciding feasibility would be a sensible computational question. But it starts from an instance-level objective discussed in prior work, not from a computational result proved here. A broader mirror of the paper’s main target, \(\beta^*\), would quantify over all voter populations and metric spaces; making that a computational problem requires choosing a finite representation and a new input model. That choice creates a research question rather than continuizing one of this paper’s results.

So the case against selecting this paper as an anchored ChoCo target is strong: none of the proponent’s candidate theorems survives as a computational anchor, and the weighted formulation does not supply one retroactively. I cannot honestly defend the stronger universal claim that no scenario makes weighted spatial voting worth studying. The finite-support population model is plausible; the negative case is strongest on the paper’s lack of a computational result to mirror.

The adversarial triple: the proponent anchors on up to three named results; the opponent sees that case and must defeat every anchor; the judge decides which case convinced it. These are the pipeline’s own outputs, generated by tools/triple_run.py — no human edited them. The paper’s own text is not reproduced here beyond the quoted statement above.