There's a theorem/lemma that states that a finite directed acyclic graph (DAG) has at least one sink and at least one source. Is there a term for a (finite) DAG with exactly one si …

I'm trying to find out whether the following graph has a name: Let $W$ be an $n$-dimensional vector space over $GF(q)$. The vertices of the graph are all the subspaces of $W$. Two …

Usually one writes $X_\bullet$ both for simplicial sets and for semisimplicial sets. But this is potentially confusing if I want to consider maps $X_\bullet\to Y_\bullet^\text{for …

Are there tetrahedra which can be subdivided into three parts similar to the original? I believe this would require splitting one face into three parts. I know some types of tetrah …

Every mathematician knows what "simplify" means, at least intuitively. Otherwise, he or she wouldn't have made it through high school algebra, where one learns to "simplify" expres …

What do you call a poset with this property? For any elements $a,b,c,d$ such that $\{a,b\}\le\{c,d\}$, there is an element x such that $\{a,b\}\le x\le\{c,d\}$. (Equivalently, for …

What is the proper terminology for a complex of sheaves $\mathcal F^\bullet$ whose homology sheaves $\mathcal H^i\mathcal F^\bullet$ vanish for $i\ne 0$?

What exactly do mathematicians mean when they refer to "the data" involved in a construction? I've encountered this many times and I can usually figure out what's going on, but I …

Is there a name for functions with the following property (a la transitive relations)? If $F(X \cup \{a\}) = y$ and $F(X \cup \{b\}) = y$ then $F(X \cup \{a,b\}) = y$

I have a question about the terminology for special values of L-functions. Is the following a correct description of standard usage: Suppose L(s) is an L-function which satisfies …

This is more of a question about terminology than about math. The term "automorphic form" is clearly a generalization of the term "modular form." What is not clear is exactly whic …

What is the correct terminology for the following property of a simplicial set $X_\bullet$: For every $k\geq 0$, every map $\partial\Delta^k\to X_\bullet$ can be extended to a …

Imagine one generates some form of random graph (e.g. a random geometric graph) and via simulation, calculates the probability that there exists an edge-wise path between all verti …

Let $\mathfrak{m}$ be a Lie sub-algebra of the Lie algebra $\mathfrak{g}$. Is there a name for the smallest ideal of $\mathfrak{g}$ containing $\mathfrak{m}$? It certainly exists a …

Is there a difference or is it just terminology? Thanks.