Lecture 4 : 3 SAT and Latin Squares
نویسنده
چکیده
This talk’s focus is on the computational complexity of completing partial Latin squares. Our first goal in this talk is to show that for many special classes of partial Latin squares, we can construct completions for these objects in polynomial time. From here, we will prove the fairly surprising claim that completing an arbitrary partial Latin square is an NP-complete task; so while it is “easy” to complete almost all reasonably-well-behaved families of partial Latin squares, it is remarkably hard to complete any partial Latin square without some constraints on what it can or cannot be.
منابع مشابه
The Search for Systems of Diagonal Latin Squares Using the SAT@home Project
In this paper we consider the approach to solving the problem of search for systems of diagonal orthogonal Latin squares in the form of the Boolean Satisfiability problem. We describe two different propositional encodings that we use. The first encoding is constructed for finding pairs of orthogonal diagonal Latin squares of order 10. Using this encoding we managed to find 17 previously unknown...
متن کاملCompleting Quasigroups or Latin Squares: A Structured Graph Coloring Problem
We introduce a graph coloring challenge benchmark based on the problem of completing Latin squares. We show how the hardness of the instances can be finely controlled by varying the fraction of precolored squares. We compare three complete (exact) solution strategies on this benchmark: (1) a Constraint Satisfaction (CSP) based approach, (2) a hybrid Linear Programming / CSP approach, and (3) a ...
متن کاملLecture 5 : Latin Squares and Magic
Today's application is to magic! Not the friendship kind, though 1 ; instead, we're going to talk about magic squares, an incredibly old piece of mathematics that we can study using Latin squares. Definition. A magic square is a n × n grid filled with the integers {0, 1,. .. n 2 − 1}, such that • each number is used exactly once in our entire grid, and • the sum of all of the entries along any ...
متن کاملOn the existence of 3-way k-homogeneous Latin trades
A μ-way Latin trade of volume s is a collection of μ partial Latin squares T1, T2, . . . , Tμ, containing exactly the same s filled cells, such that if cell (i, j) is filled, it contains a different entry in each of the μ partial Latin squares, and such that row i in each of the μ partial Latin squares contains, set-wise, the same symbols and column j, likewise. It is called μ–way k–homogeneous...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2014