作者：Boyle, M; Downarowicz, T
作者单位：University System of Maryland; University of Maryland College Park; Wroclaw University of Science & Technology
摘要：Fix a topological system (X, T), with its space K(X, T) of T-Invariant Borel probabilities. If (Y, S) is a symbolic system (subshift) and phi : (Y, S) (X, T) is a topological extension (factor map), then the function h(ext)(phi) on K(X, T) which assigns to each mu the maximal entropy of a measure nu on Y mapping to mu is called the extension entropy function of phi. The infimum of such functions over all symbolic extensions is called the symbolic extension entropy function and is denoted by h(...
作者：Kostant, B
作者单位：Massachusetts Institute of Technology (MIT)
摘要：If g is a complex simple Lie algebra, and k does not exceed the dual Coxeter number of g, then the absolute value of the k(th) coefficient of the dim g power of the Euler product may be given by the dimension of a subspace of boolean AND(k) g defined by all abelian subalgebras of g of dimension k. This has implications for all the coefficients of all the powers of the Euler product. Involved in the main results are Dale Peterson's 2(rank) theorem on the number of abelian ideals in a Borel suba...
作者：Buff, X; Chéritat, A
作者单位：Universite de Toulouse; Universite Toulouse III - Paul Sabatier
摘要：If alpha is an irrational number, we let {p(n)/q(n)}(ngreater than or equal to0), be the approximants given by its continued fraction expansion. The Bruno series B(alpha) is defined as [GRAPHICS] The quadratic polynomial P-alpha : z \--> l(2ipipialpha) z + z(2) has an indifferent fixed point at the origin. If P-alpha is linearizable, we let r(alpha) be the conformal radius of the Siegel disk and we set r(alpha) = 0 otherwise. Yoccoz proved that if B(alpha) = infinity, then r(alpha) = 0 and P-a...
