14 citations · 62 across the 19 of their papers we have counts for
22 papers
Haar decompression and amenability of Ellis flows
Daniel Max Hoffmann, Krzysztof Krupiński
Let be a tame flow and let be an Ellis group of its enveloping semigroup . Although is a compact Hausdorff topological group in its -topology, the inclus…
Of model completeness and algebraic groups
Daniel Max Hoffmann, Piotr Kowalski, Chieu-Minh Tran +1
We show that if G is a split semisimple algebraic group over a model complete field K, then the groups G(K) and G(K)' (the commutator group which is a ``Chevalley group'' as for ex…
Ranks in Ellis semigroups and model theory
Alessandro Codenotti, Daniel Max Hoffmann
We slightly generalize a notion of rank introduced by Glasner and Megrelishvili, which captures the oscillations of elements of Ellis semigroups, so that it can be applied to any c…
PAC structures as invariants of finite group actions
Daniel Max Hoffmann, Piotr Kowalski
We study model theory of actions of finite groups on substructures of a stable structure. We give an abstract description of existentially closed actions as above in terms of invar…
On rank not only in NSOP1 theories
Jan Dobrowolski, Daniel Max Hoffmann
We introduce a family of local ranks DQ depending on a finite set Q of pairs of the form (φ(x,y),q(y)) where φ(x,y) is a formula and q(y) is a global type. We prove that in any NSO…
Model theory of differential fields with finite group actions
Daniel Max Hoffmann, Omar León Sánchez
Let G be a finite group. We explore the model theoretic properties of the class of differential fields of characteristic zero in m commuting derivations equipped with a G-action by…
Model theory of fields with finite group scheme actions
Daniel Max Hoffmann, Piotr Kowalski
We study model theory of fields with actions of a fixed finite group scheme. We prove the existence and simplicity of a model companion of the theory of such actions, which general…
Thorn forking, weak normality, and theories with selectors
Daniel Max Hoffmann, Anand Pillay
We discuss the role of weakly normal formulas in the theory of thorn forking, as part of a commentary on the paper "Thorn forking and stable forking" by Ealy and Onshuus (Rev. acad…
Stable formulas in ordered structures
Daniel Max Hoffmann, Chieu-Minh Tran, Jinhe Ye
We classify the stable formulas in the theory of Dense Linear Orders without endpoints, the stable formulas in the theory of Divisible Abelian Groups, and the stable formulas witho…
PAC structures in nutshell
Daniel Max Hoffmann
An expository paper written down after RIMS Model Theory Workshop 2018. To appear in RIMS Kokyuroku.
Co-theory of sorted profinite groups for PAC structures
Daniel Max Hoffmann, Junguk Lee
We achieve several results. First, we develop a variant of the theory of absolute Galois groups in the context of many sorted structures. Second, we provide a method for coding abs…
Elementary Equivalence Theorem for PAC structures
Jan Dobrowolski, Daniel Max Hoffmann, Junguk Lee
We generalize a well-known theorem binding the elementary equivalence relation on the level of PAC fields and the isomorphism class of their absolute Galois groups. Our results con…
Model theory of fields with free operators in positive characteristic
Özlem Beyarslan, Daniel Max Hoffmann, Moshe Kamensky +1
We give algebraic conditions about a finite algebra over a perfect field of positive characteristic, which are equivalent to the companionability of the theory of fields with "…
On Galois groups and PAC substructures
Daniel Max Hoffmann
We show that for an arbitrary stable theory T, a group G is profinite if and only if G occurs as a Galois group of some Galois extension inside a monster model of T. We prove that…
Fields with automorphism and valuation
Özlem Beyarslan, Daniel Max Hoffmann, Gönenç Onay +1
Abraham Robinson's method for finding model completions is refined and and generalized for model companions and is applied to the theory of fields equipped with both a valuation an…
Model theoretic dynamics in Galois fashion
Daniel Max Hoffmann
We investigate existentially closed models (of a quite arbitrary theory) equipped which an action of a fixed group G. We embed these structures in a monster model D of some well-ro…
Existentially closed fields with finite group actions
Daniel Max Hoffmann, Piotr Kowalski
We study algebraic and model-theoretic properties of existentially closed fields with an action of a fixed finite group. Such fields turn out to be pseudo-algebraically closed in a…
Witt vectors and separably closed fields with higher derivations
Daniel Max Hoffmann
The main scope of this short paper is to provide a modification of the axioms given by Messmer and Wood for the theory of separably closed fields of positive characteristic and fin…
A note on integrating group scheme actions
Daniel Hoffmann, Piotr Kowalski
We prove a non-integrability result concerning iterative derivations on projective line, where the iterative rule is given by a non-algebraic formal group.
On existence of canonical -bases
Daniel M. Hoffmann
We describe a general method for expanding a truncated G-iterative Hasse-Schmidt derivation, where G is an algebraic group. We give examples of algebraic groups for which our metho…
Existentially closed fields with G-derivations
Daniel Hoffmann, Piotr Kowalski
We prove that the theories of fields with Hasse-Schmidt derivations corresponding to actions of formal groups admit model companions. We also give geometric axiomatizations of thes…
Integrating Hasse-Schmidt derivations
Daniel Hoffmann, Piotr Kowalski
We study integrating (that is expanding to a Hasse-Schmidt derivation) derivations, and more generally truncated Hasse-Schmidt derivations, satisfying iterativity conditions given…