# Chris Calabro

• 2006
We consider the relationship between the complexities of k-SAT and those of SAT restricted to formulas of constant density. Let s<sub>k </sub> be the infimum of those c ges 0 such that k-SAT on n variables can be decided in time O(2<sup>cn</sup>) and d<sub>Delta</sub> be the infimum of those c ges 0 such that SAT on n variables and les Deltan clauses can be(More)
• 8
• 19
• 2009
We consider the satisfiability problem for circuits of limited size and/or depth. Say that an algorithm solving a Boolean satisfiability problem on n variables is improved iff it takes time O(2 cn) for some constant c < 1, i.e. iff it is exponentially better than a brute force search. We show an improved algorithm for the satisfiability problem for circuits(More)
Preface This is a set of class notes that we have been developing jointly for some years. We use them for the graduate cryptography courses that we teach at our respective institutions. Each time one of us teaches the class, he takes the token and updates the notes a bit. You might think that, within a three or four years, one would have a rather complete(More)
• 2003
We provide some evidence that Unique k-SAT is as hard to solve as general k-SAT, where k-SAT denotes the satisfiability problem for k-CNFs with at most k literals in each clause and Unique k-SAT is the promise version where the given formula has 0 or 1 solutions. Namely, defining for each k 1, s k = inf{δ 0 | ∃ a O(2 δn)-time randomized algorithm for k-SAT}(More)
• Chris Calabro
• 2008
One way to quantify how dense a multidag is in long paths is to find the largest n, m such that whichever ≤ n edges are removed, there is still a path from an original input to an original output with ≥ m edges-the larger we can make n, m, the denser is the graph. For a given n, m, we would like to lower bound the size such a graph, say in edges, at least(More)
• 2009
We resolve an open question by [3]: the exponential complexity of deciding whether a k-CNF has a solution is the same as that of deciding whether it has exactly one solution, both when it is promised and when it is not promised that the input formula has a solution. We also show that this has the same exponential complexity as deciding whether a given(More)
• 2010
We relate the exponential complexities 2 s(k)n of $\textsc {$k$-sat}$ and the exponential complexity $2^{s(\textsc {eval}(\mathrm {\varPi }_{2} 3\textsc {-cnf}))n}$ of $\textsc {eval}(\mathrm {\varPi }_{2} 3\textsc {-cnf})$ (the problem of evaluating quantified formulas of the form $\forall\vec{x} \exists\vec{y} \textsc {F}(\vec {x},\vec{y})$ where F is a(More)
We provide some evidence that Unique-SAT is as hard to solve as general-SAT, where-SAT denotes the satisfiability problem for-CNFs and Unique-SAT is the promise version where the given formula has or solutions. Namely, defining for each , a-time randomized algorithm for-SAT and, similarly, a-time randomized algorithm for Unique-SAT , we show that. As a(More)