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start [2024/04/03 12:33] – 139.124.146.3 | start [2024/04/30 14:50] – 139.124.146.3 | ||
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==== Upcoming talks ==== | ==== Upcoming talks ==== | ||
- | **April 16 2024: [[https:// | ||
- | **April 30 2024: [[https:// | + | **April 30 2024: [[https:// |
- | **May 14 2024: [[https:// | + | The recently discovered Hat is an aperiodic |
+ | monotile for the Euclidean plane, which needs a reflected | ||
+ | version for this property. The Spectre does not have this | ||
+ | (tiny) deficiency. We discuss the topological and dynamical | ||
+ | properties of the Hat tiling, how the CAP relates to it, and | ||
+ | what the long-range order of both tilings is. Finally, we | ||
+ | briefly describe the analogous structure for the Spectre tiling. | ||
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+ | **May 14 2024: [[https:// | ||
+ | |||
+ | In 2009, Shur published the following conjecture: Let $L$ be a power-free language and let $e(L)\subseteq L$ be the set of words of $L$ that can be extended to a bi-infinite word respecting the given power-freeness. If $u,v \in e(L)$ then $uwv \in e(L)$ for some word $w$. Let $L_{k, | ||
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+ | https:// | ||
**May 28 2024: [[https:// | **May 28 2024: [[https:// | ||
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==== Past talks 2024 ==== | ==== Past talks 2024 ==== | ||
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+ | **April 16 2024: [[https:// | ||
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+ | {{ seminar2024: | ||
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+ | Automatic structures are structures whose universe and relations can be represented as regular languages. It follows from the standard closure properties of regular languages that the first-order theory of an automatic structure is decidable. | ||
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+ | While existential quantifiers can be eliminated in linear time by application of a homomorphism, | ||
+ | We answer this question negatively. | ||
+ | |||
+ | In my talk, following a short introduction to the field of automatic structures, I will present the construction of a family of NFA representing automatic relations for which the minimal NFA recognising the language after a universal projection step is doubly exponential, | ||
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+ | Based on the paper: https:// | ||
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+ | Authors: Christoph Haase, R.P. | ||
+ | |||
+ | Keywords: automatic structures, universal projection, tiling problems, state complexity. | ||
+ | |||
**April 2 2024: John Campbell** // On the evaluation of infinite products involving automatic sequences// | **April 2 2024: John Campbell** // On the evaluation of infinite products involving automatic sequences// |