English

The $D$-Variant of Transfinite Hausdorff Dimension

General Topology 2024-11-13 v1

Abstract

We assign every metric space XX the value tDHD(X)t_{D}HD(X), an ordinal number or one of the symbols 1-1 or Ω\Omega, and we call it the DD-variant of transfinite Hausdorff dimension of XX. This ordinal assignment is primarily constructed by way of the DD-dimension, a transfinite dimension function consistent with the large inductive dimension on finite dimensional metric spaces while also addressing shortcomings of the large transfinite inductive dimension. Similar to Hausdorff dimension, tDHD()t_{D}HD(\cdot) is monotone with respect to subspaces, and is a bi-Lipschitz invariant. It is also non-increasing with respect to Lipschitz maps and satisfies a coarse intermediate dimension property. We also show that this new transfinite Hausdorff dimension function addresses the primary goal of transfinite Hausdorff dimension functions; to classify metric spaces with infinite Hausdorff dimension. In particular, we show that if tDHDω0t_{D}HD\geq \omega_0, then HD(X)=HD(X) = \infty. tDHD(X)<ω1t_{D}HD(X)<\omega_1 for any separable metric space, and that one can find a metrizable space with tDHD(X)t_{D}HD(X) bounded between a given ordinal and it's successive cardinal with topological dimension 00.

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Cite

@article{arxiv.2411.07454,
  title  = {The $D$-Variant of Transfinite Hausdorff Dimension},
  author = {Bryce Decker and Nathan Dalaklis},
  journal= {arXiv preprint arXiv:2411.07454},
  year   = {2024}
}

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16 pages