Cusp summations and cusp relations of simple quad lenses

Cusp algebras

By a cusp V we shall mean the image of the unit disk D under a bounded injective holomorphic map h into C whose derivative vanishes at exactly one point. The simplest example is the Neil parabola, given by h(ζ) = (ζ, ζ). See [3, 4] for background and theory on the Neil parabola, which is pictured in Figure 1. A generalization of a cusp is a petal. A petal is the image of the unit disk D under a...

Unfolding the Cusp-Cusp Bifurcation of Planar Endomorphisms

Abstract. In many applications of practical interest, for example, in control theory, economics, electronics and neural networks, the dynamics of the system under consideration can be modelled by an endomorphism, which is a discrete smooth map that does not have a uniquely defined inverse; one also speaks simply of a noninvertible map. In contrast to the better known case of a dynamical system ...

Families of Cusp Forms

1. Families of cusp forms and the local equidistribution problem 2 2. Families of L-functions 6 3. Analogy with sieve 8 4. Examples of local equidistribution 8 5. Families of cusp forms according to Sarnak’s letter 11 6. Families of L-functions according to Conrey, Farmer, Keating, Rubinstein and Snaith 13 7. Direct consequences of strong local equidistribution 14 8. Quantitative local equidist...

Dynamical Cusp Regeneration

After being destroyed by a binary supermassive black hole, a stellar density cusp can regrow at the center of a galaxy via energy exchange between stars moving in the gravitational field of the single, coalesced hole. We illustrate this process via high-accuracy N-body simulations. Regeneration requires roughly one relaxation time and the new cusp extends to a distance of roughly one-fifth the ...

Billiards inside a Cusp