An explicit expression is obtained for the generating series for the number of ramified coverings of the sphere by the torus, with elementary branch points and prescribed ramification type over infinity. This proves a conjecture of Goulden, Jackson, and Vainshtein for the explicit number of such cov
Catalan numbers and branched coverings by the Riemann sphere
β Scribed by Lisa R Goldberg
- Publisher
- Elsevier Science
- Year
- 1991
- Tongue
- English
- Weight
- 601 KB
- Volume
- 85
- Category
- Article
- ISSN
- 0001-8708
No coin nor oath required. For personal study only.
β¦ Synopsis
We prove that the number of PGL(2. C) equivalence classes of degree d rational maps with a fixed branch set is generically equal to the "Catalan number" p(d) = (l/d)( 2j:f).
Several (previously known) applications of Catalan numbers to combinatorics and algebraic geometry are discussed throughout the course of the article.
π SIMILAR VOLUMES
An explicit expression is obtained for the generating series for the number of ramified coverings of the sphere by the double torus, with elementary branch points and prescribed ramification type over infinity. Thus we are able to determine various linear recurrence equations for the numbers of thes
Zeppelin models was retested. These tests were made at tank pressures varying from I to 20 atmospheres, and the extreme range of Reynolds Number was about I,OOO,OOO to 40,000,000. The lift, drag, and moment coefficients of the models were determined, and the effects upon these coefficients of pitc