Given a constant number d of n×n matrices with total m non-infinity entries, we show how to construct in (essentially optimal) O˜(mn+n2) time a data structure that can compute in (essentially optimal) O˜(n2) time the distance product of these matrices after incrementing the value (possibly to infinity) of a constant number k of entries. Our result is obtained by designing an oracle for single source

A blockchain is designed to be a self-sufficient decentralised ledger: a peer verifying the validity of past transactions only needs to download the blockchain (the ledger) and nothing else. However, it might be of interest to make two different blockchains interoperable, i.e., to allow one to transmit information from one blockchain to another blockchain. In this paper, we give a formalisation of

In 2014, Mesnager proposed two open problems in [4, IEEE TIT, 60(7): 4397-4407, 2014] on the construction of bent functions. One problem has been settled by Tang et al. in 2017. However, the other is still outstanding, which is solved in this letter by considering a class of PS− vectorial bent functions.

We revisit the notions of cryptographic anonymity and share unpredictability in secret sharing, introducing more systematic and fine grained definitions. We derive tight negative and positive results characterizing access structures with respect to the generalized definitions.

In the sequential setting, a decades-old fundamental result in online algorithms states that if there is a c-competitive randomized online algorithm against an adaptive, offline adversary, then there is a c-competitive deterministic algorithm. The adaptive, offline adversary is the strongest adversary among the ones usually considered, so the result states that if one has to be competitive against

It is well known that in a bipartite (and more generally in a König-Egerváry) graph, the size of the minimum vertex cover is equal to the size of the maximum matching. We first address the question whether (and if not, when) this property still holds in a König-Egerváry graph if we consider vertex covers containing a given subset of vertices. We characterize such graphs using the classic notions of

We revisit the following problem: Given a convex polygon P, find the largest-area inscribed triangle. We prove by counterexample that the linear-time algorithm presented in 1979 by Dobkin and Snyder [5] for solving this problem fails, as well as a renewed analysis of the problem. We also provide a counterexample proving that their algorithm fails finding the largest-area inscribed quadrilateral. Combined

The VC-dimension, which has wide uses in learning theory, has been used in the analysis and design of graph algorithms recently. In this paper, we study the problem of bounding the VC-dimension of unique round-trip shortest path set systems (URTSP), which are set systems induced by sets of vertices in unique round-trip shortest paths in directed graphs. We first show that different from the VC-dimensions

Minimizing the Boolean circuit implementation of a given cryptographic function is an important issue. A number of papers [1], [2], [3], [4] only consider cancellation-free straight-line programs for producing small circuits over GF(2). Cancellation is allowed by the Boyar-Peralta (BP ) heuristic [5, 6]. This yields a valuable tool for practical applications such as building fast software and low-power

We consider the problem of pattern matching with k mismatches, where there can be don't care or wild card characters in the pattern. Specifically, given a pattern P of length m and a text T of length n, we want to find all occurrences of P in T that have no more than k mismatches. The pattern can have don't care characters, which match any character. Without don't cares, the best known algorithm for

We study the characteristics of straight skeletons of monotone polygonal chains and use them to devise an algorithm for computing positively weighted straight skeletons of monotone polygons. Our algorithm runs in [Formula: see text] time and [Formula: see text] space, where n denotes the number of vertices of the polygon.

In this paper, we study several interesting intensity map splitting (IMSp) problems that arise in Intensity-Modulated Radiation Therapy (IMRT), a state-of-the-art radiation therapy technique for cancer treatments. In current clinical practice, a multi-leaf collimator (MLC) with a maximum leaf spread is used to deliver the prescribed intensity maps (IMs). However, the maximum leaf spread of an MLC may