Search results for "string"
showing 10 items of 381 documents
Näkemys oikeudenmukaisuudesta ja kihlakunnantuomarin viraltapano 1700-luvun puolivälin Vanhassa Suomessa
2021
Sven Johan Östring hoiti Vanhassa Suomessa sijainneen Savonlinnan tuomiokunnan kihlakunnantuomarin virkaa reilun vuosikymmen ajan keväästä 1747 kesään 1760. Kihlakunnantuomarin ja tuomiokunnan rahvaan välit kärjistyivät 1750-luvun lopulla talonpoikien valittaessa toistuvasti tuomari Östringin väärinkäytöksistä. Talonpoikien mukaan kihlakunnantuomari Östring oli heidän vihamiehensä. Artikkelissa kysytään, miten virkavirhevalitusprosessit etenivät ja mitkä syyt johtivat lopulta kihlakunnantuomarin viraltapanoon. Kihlakunnantuomari Östringin väärinkäytökset olivat luonteeltaan pääasiassa taloudellisia. Valituksissa korostui kuitenkin taloudellisia menetyksiä vahvemmin talonpoikien näkemys oike…
Analytic second derivatives for general coupled-cluster and configuration-interaction models.
2004
Analytic second derivatives of energy for general coupled-cluster (CC) and configuration-interaction (CI) methods have been implemented using string-based many-body algorithms. Wave functions truncated at an arbitrary excitation level are considered. The presented method is applied to the calculation of CC and CI harmonic frequencies and nuclear magnetic resonance chemical shifts up to the full CI level for some selected systems. The present benchmarks underline the importance of higher excitations in high-accuracy calculations.
Spin-Wave Driven Bidirectional Domain Wall Motion in Kagome Antiferromagnets
2021
We predict a mechanism to controllably manipulate domain walls in kagome antiferromagnets via a single linearly polarized spin-wave source. We show by means of atomistic spin dynamics simulations of antiferromagnets with kagome structure that the speed and direction of the domain wall motion can be regulated by only tuning the frequency of the applied spin-wave. Starting from microscopics, we establish an effective action and derive the corresponding equations of motion for the spin-wave-driven domain wall. Our analytical calculations reveal that the coupling of two spin-wave modes inside the domain wall explains the frequency-dependent velocity of the spin texture. Such a highly tunable sp…
Combinatorial isomorphism between Fibonacci classes
2008
Abstract In 1985 Simion and Schmidt showed that the set S n (T 3) of length n permutations avoiding the set of patterns T 3={123, 132, 213} is counted by (the second order) Fibonacci numbers. They also presented a constructive bijection between the set F n–1 of length (n–1) binary strings with no two consecutive 1s and S n (T 3). In 2005, Egge and Mansour generalized the first Simion-Simion’s result and showed that S n (T p ), the set of permutations avoiding the patterns T p ={12…p, 132, 213}, is counted by the (p–1)th order Fibonacci numbers. In this paper we extend the second Simion-Schmidt’s result by giving a bijection between the set of length (n–1) binary strings with no (p–1) consec…
On the use of relational expressions in the design of efficient algorithms
2005
Relational expressions have finite binary relations as arguments and the operations are composition (·), closure (*), inverse (−1), and union (U). The efficient computation of the relation denoted by a relational expression is considered, and a tight bound is established on the complexity of the algorithm suggested by Hunt, Szymanski and Ullman. The result implies a unified method for deriving efficient algorithms for many problems in parsing. For example, optimal algorithms are derived for strong LL(1) and strong LL(2) parser construction and an efficient polynomialtime algorithm is derived for determining the inessential error entries in an LR(1) parsing table.
Periodicity and repetitions in parameterized strings
2008
AbstractOne of the most beautiful and useful notions in the Mathematical Theory of Strings is that of a Period, i.e., an initial piece of a given string that can generate that string by repeating itself at regular intervals. Periods have an elegant mathematical structure and a wealth of applications [F. Mignosi and A. Restivo, Periodicity, Algebraic Combinatorics on Words, in: M. Lothaire (Ed.), Cambridge University Press, Cambridge, pp. 237–274, 2002]. At the hearth of their theory, there are two Periodicity Lemmas: one due to Lyndon and Schutzenberger [The equation aM=bNcP in a free group, Michigan Math. J. 9 (1962) 289–298], referred to as the Weak Version, and the other due to Fine and …
Dyck paths with a first return decomposition constrained by height
2018
International audience; We study the enumeration of Dyck paths having a first return decomposition with special properties based on a height constraint. We exhibit new restricted sets of Dyck paths counted by the Motzkin numbers, and we give a constructive bijection between these objects and Motzkin paths. As a byproduct, we provide a generating function for the number of Motzkin paths of height k with a flat (resp. with no flats) at the maximal height. (C) 2018 Elsevier B.V. All rights reserved.KeywordsKeyWords Plus:STATISTICS; STRINGS
On Table Arrangements, Scrabble Freaks, and Jumbled Pattern Matching
2010
Given a string s, the Parikh vector of s, denoted p(s), counts the multiplicity of each character in s. Searching for a match of Parikh vector q (a “jumbled string”) in the text s requires to find a substring t of s with p(t) = q. The corresponding decision problem is to verify whether at least one such match exists. So, for example for the alphabet Σ = {a, b, c}, the string s = abaccbabaaa has Parikh vector p(s) = (6,3,2), and the Parikh vector q = (2,1,1) appears once in s in position (1,4). Like its more precise counterpart, the renown Exact String Matching, Jumbled Pattern Matching has ubiquitous applications, e.g., string matching with a dyslectic word processor, table rearrangements, …
Characterization and Extraction of Irredundant Tandem Motifs
2012
We address the problem of extracting pairs of subwords (m1,m2) from a text string s of length n, such that, given also an integer constant d in input, m1 and m2 occur in tandem within a maximum distance of d symbols in s. The main effort of this work is to eliminate the possible redundancy from the candidate set of the so found tandem motifs. To this aim, we first introduce the concept of maximality, characterized by four specific conditions, that we show to be not deducible by the corresponding notion of maximality already defined for "simple" (i.e., non tandem) motifs. Then, we further eliminate the remaining redundancy by defining the concept of irredundancy for tandem motifs. We prove t…
Efficient algorithm for learning simple regular expressions from noisy examples
1994
We present an efficient algorithm for finding approximate repetitions in a given sequence of characters. First, we define a class of simple regular expressions which are of star-height one and do not contain union operations, and a stochastic mutation process of a given length over a string of characters. Then, assuming that a given string of characters is obtained corrupted by the defined mutation process from some long enough word generated by a simple regular expression, we try to restore the expression. We prove that to within some reasonable accuracy it is always possible if the length of the mutation process is bounded comparing to the length of the example. We provide an algorithm by…