Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Squirals and beyond: Substitution tilings with singular continuous
  spectrum   The squiral inflation rule is equivalent to a bijective block substitution
rule and leads to an interesting lattice dynamical system under the action of
$\mathbb{Z}^{2}$. In particular, its balanced version has purely singular
continuous diffraction. The dynamical spectrum is of mixed type, with pure
point and singular continuous components. We present a constructive proof that
admits a generalisation to bijective block substitutions of trivial height on
$\mathbb{Z}^{d}$.

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The categories of this paper are: stat
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The categories of this paper are: hep-ph
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The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph
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The categories of this paper are: econ
30
The categories of this paper are: q-alg
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The categories of this paper are: nucl-th
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The categories of this paper are: physics
28
The categories of this paper are: alg-geom
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The categories of this paper are: chem-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
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The categories of this paper are: cond-mat
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The categories of this paper are: supr-con
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The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol