In function inversion, we are given a function f : [N] (sic) [N], and want to prepare some advice of size S, such that we can efficiently invert any image in time T. This is a well studied problem with profound connec...
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ISBN:
(纸本)9781728196213
In function inversion, we are given a function f : [N] (sic) [N], and want to prepare some advice of size S, such that we can efficiently invert any image in time T. This is a well studied problem with profound connections to cryptography, data structures, communication complexity, and circuit lower bounds. Investigation of this problem in the quantum setting was initiated by Nayebi, Aaronson, Belovs, and Trevisan (2015), who proved a lower bound of ST2 = (Omega) over tilde (N) for random permutations against classical advice, leaving open an intriguing possibility that Grover's search can be sped up to time (Omega) over tilde(root N/S). Recent works by Hhan, Xagawa, and Yamakawa (2019), and Chung, Liao, and Qian (2019) extended the argument for random functions and quantum advice, but the lower bound remains ST2 = (Omega) over tilde (N). In this work, we prove that even with quantum advice, ST + T-2 = (N) is required for an algorithm to invert random functions. This demonstrates that Grover's search is optimal for S = (Omega) over tilde (v N), ruling out any substantial speed-up for Grover's search even with quantum advice. Further improvements to our bounds would imply new classical circuit lower bounds, as shown by Corrigan-Gibbs and Kogan (2019). To prove this result, we develop a general framework for establishing quantum time-space lower bounds. We further demonstrate the power of our framework by proving the following results. Yao's box problem: We prove a tight quantum time-space lower bound for classical advice. For quantum advice, we prove a first time-space lower bound using shadow tomography. These results resolve two open problems posted by Nayebi et al (2015). Salted cryptography: We show that "salting generically provably defeats preprocessing," a result shown by Coretti, Dodis, Guo, and Steinberger (2018), also holds in the quantum setting. In particular, we prove quantum time-space lower bounds for a wide class of salted cryptographic primitives in
Mobius transformation is a very important information inversion tool. Mobius transformation is sought after by many experts and scholars at home and abroad, and is a hot research topic at present. Mobius transformatio...
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Mobius transformation is a very important information inversion tool. Mobius transformation is sought after by many experts and scholars at home and abroad, and is a hot research topic at present. Mobius transformation can use the known information to reverse the unknown information, indicating that it has a strong ability to process information. Generalized evidence theory is an extension of classical evidence theory. When belief degree of the null subset is 0, then the generalized evidence theory will be degenerated as classical Dempster-Shafer evidence theory. However, how to apply Mobius transformation to generalized evidence theory is still an open problem. This paper proposes Mobius transformation in generalized evidence theory, which can perform function inversion of generalized evidence theory effectively. Numerical examples are used to prove the validity of Mobius transformation in generalized evidence theory. The experimental results show that the Mobius transformation in generalized evidence theory can effectively invert the generalized evidence theory and is a very effective function inversion method.
Raphael Robinson showed that all primitive recursive functions, depending on one argument, and only they could be obtained from two functions s(x) = x + 1 and q(x) = x divided by [root x](2) by using the operations of...
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Raphael Robinson showed that all primitive recursive functions, depending on one argument, and only they could be obtained from two functions s(x) = x + 1 and q(x) = x divided by [root x](2) by using the operations of addition+, superposition*, and iteration i. Julia Robinson proved that, starting from the same two functions and using the operations of addition+, superposition*, and the operation(-1) of function inversion, one could obtain all general recursive functions (under a certain condition on the inversion operation) and all partial recursive functions. On the basis of these results, A.I. Mal'tsev introduced into consideration Raphael Robinson algebra of all unary primitive recursive functions and two of Julia Robinson's algebras: namely, the partial algebra of all unary general recursive functions and the algebra of all unary partial recursive functions, and proposed to study the properties of these algebras, including the existence of finite bases of identities in these algebras. In this paper, we show that there is no finite basis of identities in any of the above algebras.
The Perebor (Russian for "brute-force search") conjectures, which date back to the 1950s and 1960s are some of the oldest conjectures in complexity theory. The conjectures are a stronger form of the NP P con...
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ISBN:
(纸本)9783959773096
The Perebor (Russian for "brute-force search") conjectures, which date back to the 1950s and 1960s are some of the oldest conjectures in complexity theory. The conjectures are a stronger form of the NP P conjecture (which they predate) and state that for "meta-complexity" problems, such as the Time-bounded Kolmogorov complexity Problem, and the Minimum Circuit Size Problem, there are no better algorithms than brute force search. In this paper, we disprove the non-uniform version of the Perebor conjecture for the Time Bounded Kolmogorov complexity problem. We demonstrate that for every polynomial t("), there exists of a circuit of size 24/5 (.) that solves the t(.)-bounded Kolmogorov complexity problem on every instance. Our algorithm is black-box in the description of the Universal Turing Machine U employed in the definition of Kolmogorov Complexity and leverages the characterization of one-way functions through the hardness of the time-bounded Kolmogorov complexity problem of Liu and Pass (FOCS'20), and the time-space trade-off for one-way functions of Fiat and Naor (STOC'91). We additionally demonstrate that no such black-box algorithm can have circuit size smaller than 2'0 '("'). Along the way (and of independent interest), we extend the result of Fiat and Naor and demonstrate that any efficiently computable function can be inverted (with probability 1) by a circuit of size 24'/5 (');as far as we know, this yields the first formal proof that a non-trivial circuit can invert any efficient function.
A compression problem is defined with respect to an efficient encoding function 5;given a string G, our task is to find the shortest y such that f (y) = G. The obvious brute-force algorithm for solving this compressio...
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ISBN:
(纸本)9798400703836
A compression problem is defined with respect to an efficient encoding function 5;given a string G, our task is to find the shortest y such that f (y) = G. The obvious brute-force algorithm for solving this compression task on n-bit strings runs in time O(2(l) center dot t(n)), where l is the length of the shortest description y and t(n) is the time complexity of 5 when it prints n-bit output. We prove that every compression problem has a Boolean circuit family which finds short descriptions more eficiently than brute force. In particular, our circuits have size 2(4l/5) center dot poly(t(n)), which is significantly more efficient for all l >> logt(n)). Our construction builds on Fiat-Naor's data structure for function inversion [SICOMP 1999]: we show how to carefully modify their data structure so that it can be nontrivially implemented using Boolean circuits, and we show how to utilize hashing so that the circuit size is only exponential in the description length. As a consequence, the Minimum Circuit Size Problem for generic fan-in two circuits of size s(n) on truth tables of size 2(n) can be solved by circuits of size 2(4/5) (center dot) (w+o (w)) center dot poly(2(n)), where w = s(n) log(2)(s(n) + n). This improves over the brute-force approach of trying all possible size-s(n) circuits for all s(n) >= n. Similarly, the task of computing a short description of a string x when its K-t-complexity is at most l, has circuits of size 2(4/5l) center dot poly(t). We also give non-trivial circuits for computing Kt complexity on average, and for solving NP relations with "compressible" instance-witness pairs.
Adaptation to specific processor precision is illustrated for procedures for evaluating the ratios A(k) = I1(k)/Io(k) and B(k) = 115(K)/I05(K), which provide the expected value R of the mean modulus of random umt vect...
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