Nam Hung Tran Nguyen

I. Các khách sạn của các tập đoàn lớn trên thế giới tại các thành phố ở Đức 1. Munich   1.1. Hilton Munich Airport     Địa chỉ:   Terminalstraße Mitte 20, 85356 München-Flughafen, Đức 1.2.  Sofitel Munich Bayerpost Hotel     Địa chỉ:   Bayerstraße 12, 80335 München, Đức 2. Hamburg   2.1.  Movenpick Hotel Hamburg    Địa chỉ: Sternschanze 6, 20357 Hamburg, Đức 2.2.  Hamburg Marriott Hotel     Địa chỉ:   ABC-Straße 52, 20354 Hamburg, Đức 3. Berlin 3.1.  Crowne Plaza Berlin City Centre By IHG     Địa chỉ:   Nürnberger Str. 65, 10787 Berlin, Đức 3.2. Hilton Berlin Hotel    Địa chỉ:   Mohrenstraße 30, 10117 Berlin, Đức 3.3. Pullman Berlin Schweizerhof Hotel     Địa chỉ:   Budapester Str. 25, 10787 Berlin, Đức 4. Frankfurt 4.1. JW Marriott Hotel Frankfurt     Địa chỉ:   4.2. Hilton Frankfurt City Centre     Địa chỉ:  4.3. Sof...

1. Existence of left-invariant mean    Let G be a group. Denote by l^{\infty}(G, R) the (Banach) space of bounded functions from G to the set R of real numbers. A left-invariant mean  on a group G is an R-linear map m: l^{\infty}(G, R) -> R satisfying the following properties:     (i) (Normalization) m(1) = 1    (ii) (Positivity) If f(g) >= 0 for all g in G, we have m(f) >= 0  (iii) (Left-invariance) For all g in G and f in l^{\infty}(G, R), we have m(gf) = m(f). Here gf is the function f* satisfying f*(a) = f(ga) for all a in G.      The group is amenable if it admits a left-invariant mean.  Example 1: If G is a finite group, G is amenable. Indeed, if we define m(f) to be the average of all the numbers f(g) with g in G, the action of any element doesn't change this average since this action sends G to itself. The two other properties are also obvious.  2. Amenable graphs and Folner sequences   ...