Banaji, Amlan; Fraser, Jonathan M. Intermediate dimensions of infinitely generated attractors. (English) Zbl 1547.28014 Trans. Am. Math. Soc. 376, No. 4, 2449-2479 (2023). Summary: We study the dimension theory of limit sets of iterated function systems consisting of a countably infinite number of contractions. Our primary focus is on the intermediate dimensions: a family of dimensions depending on a parameter \(\theta \in [0,1]\) which interpolate between the Hausdorff and box dimensions. Our main results are in the case when all the contractions are conformal. Under a natural separation condition we prove that the intermediate dimensions of the limit set are the maximum of the Hausdorff dimension of the limit set and the intermediate dimensions of the set of fixed points of the contractions. This builds on work of Mauldin and Urbański concerning the Hausdorff and upper box dimension. We give several (often counter-intuitive) applications of our work to dimensions of projections, fractional Brownian images, and general Hölder images. These applications apply to well-studied examples such as sets of numbers which have real or complex continued fraction expansions with restricted entries. We also obtain several results without assuming conformality or any separation conditions. We prove general upper bounds for the Hausdorff, box and intermediate dimensions of infinitely generated attractors in terms of a topological pressure function. We also show that the limit set of a ‘generic’ infinite iterated function system has box and intermediate dimensions equal to the ambient spatial dimension, where ‘generic’ can refer to any one of (i) full measure; (ii) prevalent; or (iii) comeagre. Cited in 6 Documents MSC: 28A80 Fractals 37B10 Symbolic dynamics 11K50 Metric theory of continued fractions Keywords:infinite iterated function system; conformal iterated function system; intermediate dimensions; Hausdorff dimension; box dimension; topological pressure function; continued fractions × Cite Format Result Cite Review PDF Full Text: DOI arXiv References: [1] Banaji, Amlan, Generalised intermediate dimensions · Zbl 1509.28005 [2] Amlan Banaji and Jonathan M. Fraser, Assouad type dimensions of infinitely generated self-conformal sets. Preprint, 2207.11611, 2022. [3] Banaji, Amlan, Intermediate dimensions of Bedford-Mcmullen carpets with applications to Lipschitz equivalence · Zbl 1509.28005 [4] Banaji, Amlan, Attainable forms of intermediate dimensions, Ann. Fenn. Math., 939-960 (2022) · Zbl 1509.28005 · doi:10.54330/afm.120529 [5] Burrell, Stuart A., Dimensions of fractional Brownian images, J. Theoret. Probab. 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