Lattice word
In mathematics, a lattice word (or lattice permutation) is a string composed of positive integers, in which every prefix contains at least as many positive integers i as integers i + 1.
A reverse lattice word, or Yamanouchi word, is a string whose reversal is a lattice word.
Examples
For instance, 11122121 is a lattice permutation, so 12122111 is a Yamanouchi word, but 12122111 is not a lattice permutation, since the sub-word 12122 contains more two's than one's.
gollark: What problems? We mostly don't get mauled by animals and die of tuberculosis and whatnot.
gollark: They still don't actually have any access to medicine.
gollark: They're very different cultures. There are more factors than "has technology" or not.
gollark: So extreme poverty is not obviously bad but suicide *is* somehow obviously bad?
gollark: Wow, great justification!
See also
- Dyck word
References
- Fulton, William (1997), Young tableaux, London Mathematical Society Student Texts, 35, Cambridge University Press, ISBN 978-0-521-56724-4, MR 1464693
- Macdonald, Ian G. (1995), Symmetric functions and Hall polynomials, Oxford Mathematical Monographs (Second ed.), The Clarendon Press and Oxford University Press, ISBN 0-19-853489-2, MR 1354144
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