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0  The functor $\mathsf{Sym}_A$ is left adjoint to the forgetful one $A\text-\mathsf{cdga}_{\leq0}\to A\text-\mathsf{dg\text-mod}_{\leq0}$, where $A\in k\text-\mathsf{cdga}_{\leq0}$. I have troubles computing $\mathsf{Hom}_{k\text-\mathsf{cdga}_{\leq0}}(\mathsf{Sym}_A(X),B)$. Intuitively, it seems ...

A new tag created by Yanior Weg. The same user also created a tag-excerpt.
2  Problem. Let $G$ be a graph with a $K_5$ minor. Prove that $G$ contains either a $K_5$ or a $K_{3,3}$ topological minor. I'm having a hard time believing this result. Consider the graph $G$ obtained from $K_5$ by replacing one of its vertices with a cycle of length 4: Where is the $K_5$ or $K... 0  I'm having some confusion with proposition$1.72$of the Diestal book on Graph Theory which states that (ii) If$\Delta(X) \leq 3$, then every$MX$contains$TX$thus every minor with maximum degree$3$is also it's topological minor. I feel as if i've found a counter-example which of course ... 4  If$H$has maximum vertex degree at most$3$(so$\Delta(H)\leq 3$) and$H$is a minor of$G$, then$H$is a topological minor of$G$. The converse follows by definition. However, most sources state this proposition without a proof. Any help is greatly appreciated. 1  A topological minor of$\Gamma$is a graph, obtained form a subgraph of$\Gamma$by collapsing paths of degree-two vertices to single edges A minor of$\Gamma$is a graph, obtained form a subgraph of$\Gamma\$ by arbitrary edge contractions. It is not hard to see, that any topological minor is ...