An example of a Fraissé class without a Katětov functor

0485662 - MÚ 2019 RIV NL eng J - Journal Article
Grebík, Jan
An example of a Fraissé class without a Katětov functor.
Applied Categorical Structures. Roč. 26, č. 1 (2018), s. 1-6. ISSN 0927-2852. E-ISSN 1572-9095
R&D Projects: GA ČR GF16-34860L
Institutional support: RVO:67985840
Keywords : Katětov functor * Fraissé limit
OECD category: Pure mathematics
Impact factor: 0.552, year: 2018
https://link.springer.com/article/10.1007%2Fs10485-016-9469-4

We disprove a conjecture from Kubiś and Mašulović [2] by showing the existence of a Fraissé class C which does not admit a Katětov functor. On the other hand, we show that the automorphism group of the Fraissé limit of C is universal, as it happens in the presence of a Katětov functor.
Permanent Link: http://hdl.handle.net/11104/0280624