A Generalized Arithmetic-Geometric Mean

SIAM Review ◽  
1983 ◽  
Vol 25 (3) ◽  
pp. 401-401 ◽  
Author(s):  
D. Borwein ◽  
P. B. Borwein
2011 ◽  
Vol 07 (01) ◽  
pp. 173-202
Author(s):  
ROBERT CARLS

In this article, we give a Galois-theoretic characterization of the canonical theta structure. The Galois property of the canonical theta structure translates into certain p-adic theta relations which are satisfied by the canonical theta null point of the canonical lift. As an application, we prove some 2-adic theta identities which describe the set of canonical theta null points of the canonical lifts of ordinary abelian varieties in characteristic 2. The latter theta relations are suitable for explicit canonical lifting. Using the theory of canonical theta null points, we are able to give a theoretical foundation to Mestre's point counting algorithm which is based on the computation of the generalized arithmetic geometric mean sequence.


2010 ◽  
Vol 21 (07) ◽  
pp. 939-949 ◽  
Author(s):  
KEIJI MATSUMOTO ◽  
TOMOHIDE TERASOMA

In this paper, we define a generalized arithmetic-geometric mean μg among 2g terms motivated by 2τ-formulas of theta constants. By using Thomae's formula, we give two expressions of μg when initial terms satisfy some conditions. One is given in terms of period integrals of a hyperelliptic curve C of genus g. The other is by a period integral of a certain Calabi–Yau g-fold given as a double cover of the g-dimensional projective space Pg.


SIAM Review ◽  
1984 ◽  
Vol 26 (3) ◽  
pp. 433-433
Author(s):  
D. Borwein

10.37236/2915 ◽  
2013 ◽  
Vol 20 (3) ◽  
Author(s):  
Karl Mahlburg ◽  
Clifford Smyth

We prove generalized arithmetic-geometric mean inequalities for quasi-means arising from symmetric polynomials. The inequalities are satisfied by all positive, homogeneous symmetric polynomials, as well as a certain family of non-homogeneous polynomials; this family allows us to prove the following combinatorial result for marked square grids.Suppose that the cells of a $n \times n$ checkerboard are each independently filled or empty, where the probability that a cell is filled depends only on its column. We prove that for any $0 \leq \ell \leq n$, the probability that each column has at most $\ell$ filled sites is less than or equal to the probability that each row has at most $\ell$ filled sites.


2012 ◽  
Vol 28 (1) ◽  
pp. 61-78 ◽  
Author(s):  
Jeroen Spandaw ◽  
Duco van Straten

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Yuangong Sun

By using a generalized arithmetic-geometric mean inequality on time scales, we study the forced oscillation of second-order dynamic equations with nonlinearities given by Riemann-Stieltjes integrals of the form[p(t)ϕα(xΔ(t))]Δ+q(t)ϕα(x(τ(t)))+∫aσ(b)r(t,s)ϕγ(s)(x(g(t,s)))Δξ(s)=e(t), wheret∈[t0,∞)T=[t0,∞)  ⋂  T,Tis a time scale which is unbounded from above;ϕ*(u)=|u|*sgn u;γ:[a,b]T1→ℝis a strictly increasing right-dense continuous function;p,q,e:[t0,∞)T→ℝ,r:[t0,∞)T×[a,b]T1→ℝ,τ:[t0,∞)T→[t0,∞)T, andg:[t0,∞)T×[a,b]T1→[t0,∞)Tare right-dense continuous functions;ξ:[a,b]T1→ℝis strictly increasing. Some interval oscillation criteria are established in both the cases of delayed and advanced arguments. As a special case, the work in this paper unifies and improves many existing results in the literature for equations with a finite number of nonlinear terms.


2006 ◽  
Vol 45 (01) ◽  
pp. 57-61
Author(s):  
M. Puille ◽  
D. Steiner ◽  
R. Bauer ◽  
R. Klett

Summary Aim: Multiple procedures for the quantification of activity leakage in radiation synovectomy of the knee joint have been described in the literature. We compared these procedures considering the real conditions of dispersion and absorption using a corpse phantom. Methods: We simulated different distributions of the activity in the knee joint and a different extra-articular spread into the inguinal lymph nodes. The activity was measured with a gammacamera. Activity leakage was calculated by measuring the retention in the knee joint only using an anterior view, using the geometric mean of anterior and posterior views, or using the sum of anterior and posterior views. The same procedures were used to quantify the activity leakage by measuring the activity spread into the inguinal lymph nodes. In addition, the influence of scattered rays was evaluated. Results: For several procedures we found an excellent association with the real activity leakage, shown by an r² between 0.97 and 0.98. When the real value of the leakage is needed, e. g. in dosimetric studies, simultaneously measuring of knee activity and activity in the inguinal lymph nodes in anterior and posterior views and calculation of the geometric mean with exclusion of the scatter rays was found to be the procedure of choice. Conclusion: When measuring of activity leakage is used for dosimetric calculations, the above-described procedure should be used. When the real value of the leakage is not necessary, e. g. for comparing different therapeutic modalities, several of the procedures can be considered as being equivalent.


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