Given a partition of a graph into connected components, the membership oracle asserts whether any two vertices of the graph lie in the same component or not. We prove that for n >= k >= 2, learning the component...
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Given a partition of a graph into connected components, the membership oracle asserts whether any two vertices of the graph lie in the same component or not. We prove that for n >= k >= 2, learning the components of an n-vertex hidden graph with k components requires at least (k-1)n-((k)(2)) membership queries. Our result improves on the best known information-theoretic bound of Omega(n log k) queries, and exactly matches the query complexity of the algorithm introduced by Reyzin and Srivastava (2007) for this problem. Additionally, we introduce an oracle, with access to which one can learn the number of components of G in asymptotically fewer queries than learning the full partition, thus answering another question posed by the same authors. Lastly, we introduce a more applicable version of this oracle, and prove asymptotically tight bounds of (Theta) over tilde (m) queries for both learning and verifying an m-edge hidden graph G using it.
We establish the first tight lower bound of Omega(log log k) on the query complexity of sampling from the class of strongly log-concave and log-smooth distributions with condition number k in one dimension. Whereas ex...
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We establish the first tight lower bound of Omega(log log k) on the query complexity of sampling from the class of strongly log-concave and log-smooth distributions with condition number k in one dimension. Whereas existing guarantees for MCMC-based algorithms scale polynomially in k, we introduce a novel algorithm based on rejection sampling that closes this doubly exponential gap.
We study lower bounds on the query complexity of determining correlated equilibrium. In particular, we consider a query model in which an n-player game is specified via a black box that returns players' utilities ...
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We study lower bounds on the query complexity of determining correlated equilibrium. In particular, we consider a query model in which an n-player game is specified via a black box that returns players' utilities at pure action profiles. In this model, we establish that in order to compute a correlated equilibrium, any deterministic algorithm must query the black box an exponential (in n) number of times.
This paper employs a powerful argument, called an algorithmic argument, to prove lower bounds of the quantum query complexity of a multiple-block ordered search problem, which is a natural generalization of the ordere...
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ISBN:
(纸本)3540228233
This paper employs a powerful argument, called an algorithmic argument, to prove lower bounds of the quantum query complexity of a multiple-block ordered search problem, which is a natural generalization of the ordered search problem. Apart from much studied polynomial and adversary methods for quantum query complexity lower bounds, our argument shows that the multiple-block ordered search needs a large number of nonadaptive oracle queries on a black-box model of quantum computation that is also supplemented with advice. Our argument is also applied to the notions of computational complexity theory: quantum truth-table reducibility and quantum truth-table autoreducibility.
The main reason for query model's prominence in complexity theory and quantum computing is the presence of concrete lower bounding techniques: polynomial and adversary method. There have been considerable efforts ...
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ISBN:
(纸本)9783031522123;9783031522130
The main reason for query model's prominence in complexity theory and quantum computing is the presence of concrete lower bounding techniques: polynomial and adversary method. There have been considerable efforts to give lower bounds using these methods, and to compare/relate them with other measures based on the decision tree. We explore the value of these lower bounds on quantum query complexity and their relation with other decision tree based complexity measures for the class of symmetric functions, arguably one of the most natural and basic sets of Boolean functions. We show an explicit construction for the dual of the positive adversary method and also of the square root of private coin certificate game complexity for any total symmetric function. This shows that the two values cannot be distinguished for any symmetric function. Additionally, we show that the recently introduced measure of spectral sensitivity gives the same value as both positive adversary and approximate degree for every total symmetric Boolean function. Further, we look at the quantum query complexity of Gap Majority, a partial symmetric function. It has gained importance recently in regard to understanding the composition of randomized query complexity. We characterize the quantum query complexity of Gap Majority and show a lower bound on noisy randomized query complexity (Ben-David and Blais, FOCS 2020) in terms of quantum query complexity.
We give query complexity lower bounds for convex optimization and the related feasibility problem. We show that quadratic memory is necessary to achieve the optimal oracle complexity for first-order convex optimizatio...
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We give query complexity lower bounds for convex optimization and the related feasibility problem. We show that quadratic memory is necessary to achieve the optimal oracle complexity for first-order convex optimization with deterministic algorithms. In particular, this shows that center-of-mass cutting-planes algorithms in dimension d which use (O) over tilde (d(2)) memory and (O) over tilde (d) queries are Pareto-optimal for both convex optimization and the feasibility problem, up to logarithmic factors. Precisely, building upon techniques introduced in [23], we prove that to minimize 1-Lipschitz convex functions over the unit ball to 1/d(4) accuracy, any deterministic first-order algorithms using at most d(2-delta) bits of memory must make (Omega) over tilde (d(1+delta/3)) queries, for any delta is an element of[0, 1]. For the feasibility problem, in which an algorithm only has access to a separation oracle, we show a stronger tradeoff: for at most d(2-delta) memory, the number of queries required is (Omega) over tilde (d(1+delta)). This resolves a COLT 2019 open problem of Woodworth and Srebro.
The kth slice ([n]) of the Boolean cube {0, 1}n is the set of all n -bit strings with Hamming k weight k. We study the deterministic query complexity of Boolean functions on slices of the Boolean cube. We show that th...
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The kth slice ([n]) of the Boolean cube {0, 1}n is the set of all n -bit strings with Hamming k weight k. We study the deterministic query complexity of Boolean functions on slices of the Boolean cube. We show that there exists a function on the balanced slice ( [n]) requiring n/2 n - O (log log n) queries. We observe that there is an explicit function on the balanced slice requiring n - O (log n) queries based on independent sets in Johnson graphs. We also consider the maximum query complexity on constant-weight slices and how it relates to Ramsey theorems. (c) 2024 Elsevier B.V. All rights reserved.
We describe new lower bounds for randomized communication complexity and query complexity which we call the partition bounds. They are expressed as the optimum value of linear programs. For communication complexity we...
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ISBN:
(纸本)9780769540603
We describe new lower bounds for randomized communication complexity and query complexity which we call the partition bounds. They are expressed as the optimum value of linear programs. For communication complexity we show that the partition bound is stronger than both the rectangle/corruption bound and the gamma(2)/generalized discrepancy bounds. In the model of query complexity we show that the partition bound is stronger than the approximate polynomial degree and classical adversary bounds. We also exhibit an example where the partition bound is quadratically larger than the approximate polynomial degree and adversary bounds.
We study the composition question for bounded-error randomized query complexity: Is R(f circle g) = Omega(R(f) R(g)) for all Boolean functions f and g? We show that inserting a simple Boolean function h, whose query c...
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We study the composition question for bounded-error randomized query complexity: Is R(f circle g) = Omega(R(f) R(g)) for all Boolean functions f and g? We show that inserting a simple Boolean function h, whose query complexity is only Theta(logR(g)), in between f and g allows us to prove R(f circle h circle g) = Omega(R(f) R(h) R(g)). We prove this using a new lower bound measure for randomized query complexity we call randomized sabotage complexity, RS(f). Randomized sabotage complexity has several desirable properties, such as a perfect composition theorem, RS (f circle g) >= RS(f) RS(g), and a composition theorem with randomized query complexity, R(f circle g) = Omega(R(f) RS(g)). It is also a quadratically tight lower bound for total functions and can be quadratically superior to the partition bound, the best known general lower bound for randomized query complexity. Using this technique we also show implications for lifting theorems in communication complexity. We show that a general lifting theorem for zero-error randomized protocols implies a general lifting theorem for bounded-error protocols.
In 1986, Saks and Wigderson conjectured that the largest separation between deterministic and zero-error randomized query complexity for a total Boolean function is given by the function f on n = 2(k) bits defined by ...
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In 1986, Saks and Wigderson conjectured that the largest separation between deterministic and zero-error randomized query complexity for a total Boolean function is given by the function f on n = 2(k) bits defined by a complete binary tree of NAND gates of depth k, which achieves R-0(f) = O(D(f)(0.7)(537. )(. .)). We show that this is false by giving an example of a total Boolean function f on n bits whose deterministic query complexity is (Omega) over tilde (n) while its zero-error randomized query complexity is (O) over tilde(root n). We further show that the quantum query complexity of the same function is (O) over tilde (n(1/4)), giving the first example of a total function with a super-quadratic gap between its quantum and deterministic query complexities. We also construct a total Boolean function g on n variables that has zero-error randomized query complexity Omega(n/log(n)) and bounded-error randomized query complexity R(g) = ((O) over tilde root n). This is the first superlinear separation between these two complexity measures. The exact quantum query complexity of the same function is (Q) over tilde (E)(g) = (O) over tilde(root n). These functions show that the relations D(f) = O(R-1(f)(2)) and R-0(f) = (O) over tilde (R(f)(2)) are optimal, up to polylogarithmic factors. Further variations of these functions give additional separations between other query complexity measures: a cubic separation between Q and R-0, a 3/2-power separation between Q(E) and R, and a 4th-power separation between approximate degree and bounded-error randomized query complexity. All of these examples are variants of a function recently introduced by Goos, Pitassi, and Watson, which they used to separate the unambiguous 1-certificate complexity from deterministic query complexity and to resolve the famous Clique versus Independent Set problem in communication complexity.
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