Tobias Schlemmer
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 May 29 comment Equality-preserving embeddings of finite trees I don't understand your question. Isn't it true that every finite subset of the natural numbers is a special case of a finite set? May 17 awarded Yearling May 8 comment Galois Connections: algorithmic generation You are welcome. Today I got a literature suggestion about this topic (see edit). May 8 revised Galois Connections: algorithmic generation Added an article suggestion May 3 answered Galois Connections: algorithmic generation Mar 22 answered Has the single sorted case of formal concept analysis been investigated? Jan 17 revised What is known about orbifolding ordered groups and sets? Who has been involved? Links to Lee metrics? Added a further explanation to the question. Jan 17 awarded Commentator Jan 17 comment What is known about orbifolding ordered groups and sets? Who has been involved? Links to Lee metrics? A better description of $Λ$ would be: It describes the action that is necessary to map a tuple into the transversal if its first place is already there. Jan 17 awarded Student Sep 18 comment Does the notion of graphs with vertex multiplicity exist? A similar construction has been called binary relation orbifold (Borchmann, Daniel: Context Orbifolds, Diploma Thesis, TU Dresden, 2009, link). Sep 17 comment Conditions for a group to be lattice-ordered I think you should contact one of the authors of the corresponding papers and ask them if they can help you. It is a very special branch of mathematics and propably of the contributers are not active participants of MO. Sep 15 comment Conditions for a group to be lattice-ordered @BorisNovikov Have a look at my answer, Statement 1 (it was added before I saw your comment). The linear order that you constructed using Szpilrajn's lemma does not fulfil Xodaraps conditions. Thus, it is not a counterexample. Sep 15 answered Conditions for a group to be lattice-ordered Sep 15 comment Conditions for a group to be lattice-ordered The first implication in the proof of 2) does not hold. As in any right-ordered group the implications $x≤y ⇒ xz≤yz$ holds but not necessarily $x≤y⇒zx≤zy$. On the other hand Szpilrajn is not enough to construct a contradiction as $(\mathbb Z,≤)×(\mathbb Z,≤)$ has also linear order extension $≤_l$ that leads to $(x∨_ly)z=yz≠xz=xz∨_lyz$ for some $x,y,z$. Sep 14 comment Conditions for a group to be lattice-ordered Is every right-ordered group with a lattice order already an ordered group? If not there are counterexamples as the implications $x≤1 ⇒ xz≤z$ and similarly for $x≥1$ is a conclusion of being right-ordered. Otherwise it would be sufficient to prove that it is a right-ordered group. Sep 13 revised Self-containing graphs Some further consideration of loops. Sep 13 comment Self-containing graphs If $H$ is a proper subgraph of some finite graph $G$ then $G$ there is no injective mapping from the set of nodes of $G$ into the set of nodes of $H$. Sep 12 revised Self-containing graphs forgot to consider loops Sep 12 answered Self-containing graphs