This paper expands the role of the new field of computational topology by surveying methods for incorporating connectedness in shape modeling. Two geometric representations in particular, recurrent models and implicit surfaces, can (often unpredictably) become connected or disconnected based on typical changes in modeling parameters. Two methodologies for controlling connectedness are identifie...

We study continua on which each nonconstant open mapping is light. W. Makuchowski asked if this property is preserved under atomic mappings. It is known that this is true under an additional assumption of arcwise connectedness of the domain continuum. We show that in general this is not true.

We consider the set Ω2 of double zeros in (0, 1) for power series with coefficients in {−1, 0, 1}. We prove that Ω2 is disconnected, and estimate minΩ2 with high accuracy. We also show that [2 − η, 1) ⊂ Ω2 for some small, but explicit η > 0 (this was only known for η = 0). These results have applications in the study of infinite Bernoulli convolutions and connectedness properties of self-affine...

Given an arbitrary spacetime (M, g), we prove a simple criterion to check when many of the good properties of the time-separation (Lorentzian distance) d valid in globally hyperbolic spacetimes hold for M . Concretely, when the product P = M × R, g̃ = g + dy is causally simple, then not only M is causally simple, but also d is continuous and AvezSeifert connectedness (each two causally related e...

The ubiquity of online programs in higher education requires continued focus on designing instructional environments that improve students’ learning. We examine students’ perceptions of sense of community and learning, as well as academic achievement, using grades obtained from a final project and participation in asynchronous discussion forums. Findings indicate a significant correlation betwe...

Interpolation of two-dimensional shapes described by iterated function systems is explored. Iterated function systems define shapes using self-transformations, and interpolation of these shapes requires interpolation of these transformations. Polar decomposition is used to avoid singular intermediate transformations and to better simulate articulated motion. Unlike some other representations, s...

Introduction 1. Definitions and Elementary Results 2. When Disconnected Filled-in Julia Sets are Cantor Sets 3. Smooth Julia Sets 4. Fixed Points 5. Remarks on the Topology of the Connectedness Locus Acknowledgements References We consider the rational maps given by z jzj z c, for z and c complex and fixed and real. The case corresponds to quadratic polynomials: some of the well-known results f...

We prove the Feigenbaum-Coullet-Tresser conjecture on the hyperbolicity of the renormalization transformation of bounded type. This gives the first computer-free proof of the original Feigenbaum observation of the universal parameter scaling laws. We use the Hyperbolicity Theorem to prove Milnor’s conjectures on self-similarity and “hairiness” of the Mandelbrot set near the corresponding parame...

We prove the Feigenbaum-Coullet-Tresser conjecture on the hyperbolicity of the renormalization transformation of bounded type. This gives the first computer-free proof of the original Feigenbaum observation of the universal parameter scaling laws. We use the Hyperbolicity Theorem to prove Milnor’s conjectures on self-similarity and “hairiness” of the Mandelbrot set near the corresponding parame...