Sökning: "ring lemma"
Visar resultat 1 - 5 av 6 avhandlingar innehållade orden ring lemma.
1. On the ring lemma
Sammanfattning : The sharp ring lemma states that if n ≥ 3 cyclically tangent discs with pairwise disjoint interiors are externally tangent to and surround the unit disc, then no disc has a radius below cn = (F2n-1 + F2n-2 - 1)-1 – where Fk denotes the kth Fibonacci number – and that the lower bound is attained in essentially unique Apollonian configurations. Here we give a proof by transforming the problem to a class of strip configurations, after which we closely follow a method of proof due to Aharonov and Stephenson. LÄS MER
2. The Diamond Lemma for Power Series Algebras
Sammanfattning : The main result in this thesis is the generalisation of Bergman's diamond lemma for ring theory to power series rings. This generalisation makes it possible to treat problems in which there arise infinite descending chains. LÄS MER
3. On the Picard Group of Integer Group Rings
Sammanfattning : .... LÄS MER
4. Intersections on moduli spaces of curves
Sammanfattning : We present a new approach to perform calculations with the certain standard classes in cohomology of the moduli spaces of curves. It is based on an important lemma of Ionel relating the intersection theoriy of the moduli space of curves and that of the space of admissible coverings. LÄS MER
5. On Amoebas and Multidimensional Residues
Sammanfattning : This thesis consists of four papers and an introduction. In Paper I we calculate the second order derivatives of the Ronkin function of an affine polynomial in three variables. This gives an expression for the real Monge-Ampére measure associated to the hyperplane amoeba. LÄS MER