On a Speculated Relation Between Chvátal-Sankoff Constants of Several Sequences
نویسندگان
چکیده
It is well known that, when normalized by n, the expected length of a longest common subsequence of d sequences of length n over an alphabet of size σ converges to a constant γσ,d. We disprove a speculation by Steele regarding a possible relation between γ2,d and γ2,2. In order to do that we also obtain some new lower bounds for γσ,d, when both σ and d are small integers.
منابع مشابه
An Analysis of the Mongeau-Sankoff Algorithm for Music Information Retrieval
An essential problem in music information retrieval is to determine the similarity between two given melodies; there are several melodic similarity measures that have been proposed, among others, the Mongeau-Sankoff measure. In this work we implemented a modified version of the Mongeau-Sankoff measure. We conducted an experimental study to compare the implemented measure with other similarity m...
متن کاملHigh precision simulations of the longest common subsequence problem
The longest common subsequence problem is a long studied prototype of pattern matching problems. In spite of the effort dedicated to it, the numerical value of its central quantity, the ChvátalSankoff constant, is not yet known. Numerical estimations of this constant are very difficult due to finite size effects. We propose a numerical method to estimate the Chvátal-Sankoff constant which combi...
متن کاملWhat Kind of Data is it? Situating Sociolinguistic Corpora in Context
In my presentation I will discuss how sociolinguistic corpora can be compiled so as to document and maximize access to the context of its collection. This is no doubt a murky issue for the coding and categorization enterprise, but it is as critical as demographic information if we are going to be able to compare data sets from different communities, eras or across research projects. However, ho...
متن کاملHOW TO FORMALIZE VARIATION: STOCHASTIC OT MODELS AND /s/ DELETION IN SPANISH
The existence of variability, i.e., when multiple surface forms correspond to a single underlying representation, is a significant problem for many formal theories of phonology, which are often treated as strictly deterministic. Many theorists simply regard the different surface forms as free variants and use optional rules to formalize the variation (see Chomsky & Halle 1968). Others argue tha...
متن کاملRelation Between RNA Sequences, Structures, and Shapes via Variation Networks
Background: RNA plays key role in many aspects of biological processes and its tertiary structure is critical for its biological function. RNA secondary structure represents various significant portions of RNA tertiary structure. Since the biological function of RNA is concluded indirectly from its primary structure, it would be important to analyze the relations between the RNA sequences and t...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Combinatorics, Probability & Computing
دوره 18 شماره
صفحات -
تاریخ انتشار 2009