Letter counting
نویسندگان
چکیده
منابع مشابه
Counting `-letter subwords in compositions
Let N be the set of all positive integers and let A be any ordered subset of N. Recently, Heubach and Mansour enumerated the number of compositions of nwithm parts inA that contain the subword τ exactly r times, where τ ∈ {111, 112, 221, 123}. Our aims are (1) to generalize the above results, i.e., to enumerate the number of compositions of n with m parts in A that contain an `-letter subword, ...
متن کاملCounting l-letter subwords in compositions
Let N be the set of all positive integers and let A be any ordered subset of N. Recently, Heubach and Mansour enumerated the number of compositions of n with m parts in A that contain the subword τ exactly r times, where τ ∈ {111, 112, 221, 123}. Out aims are (1) to generalize the above results, i.e., to enumerate the number of compositions of n with m parts in A that contain an l-letter subwor...
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Large genomes are full of repeated DNA sequences. It was estimated that over half of the human DNA consists of repeated sequences (Baltimore 2001; Eichler 2001; Leem et al. 2002). Tandem duplication is one of the important evolutionary mechanisms for producing repeated DNA sequences, in which the copies that may or may not contain genes are adjacent along the genome. Fitch (1977) first observed...
متن کاملCounting Permutations Modulo Pattern-Replacement Equivalences for Three-Letter Patterns
We study a family of equivalence relations on Sn, the group of permutations on n letters, created in a manner similar to that of the Knuth relation and the forgotten relation. For our purposes, two permutations are in the same equivalence class if one can be reached from the other through a series of pattern-replacements using patterns whose order permutations are in the same part of a predeter...
متن کاملA recursive bijective approach to counting permutations containing 3-letter patterns
We present a method, illustrated by several examples, to nd explicit counts of permutations containing a given multiset of three letter patterns. The method is recursive, depending on bijections to reduce to the case of a smaller multiset, and involves a consideration of separate cases according to how the patterns overlap. Speci cally, we use the method (i) to provide combinatorial proofs of B...
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ژورنال
عنوان ژورنال: Historiographia Linguistica
سال: 2013
ISSN: 0302-5160,1569-9781
DOI: 10.1075/hl.40.3.01yca