Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options not deleted user 56833

Questions about the branch of combinatorics called graph theory (not to be used for questions concerning the graph of a function). This tag can be further specialized via using it in combination with more specialized tags such as extremal-graph-theory, spectral-graph-theory, algebraic-graph-theory, topological-graph-theory, random-graphs, graph-colorings and several others.

4 votes
0 answers
137 views

Can the vertices of a planar graph of min degree 3 be covered with edges of average weight (...

Consider a planar graph where every vertex is incident to at least 3 edges, and assign to each edge a weight equal to the sum of the degrees of its endpoints. If not, what is the smallest n so that e …
Hao S's user avatar
  • 111
5 votes
0 answers
197 views

"separators" for nonplanar graphs embedded in the plane

Given a nonplanar graph $G$ drawn in the plane with crossings. Does there exist a small ($o(|V(G)|$) subset $S$ of edges of $G$ such that after the removal of all edges that intersect or share an endp …
Hao S's user avatar
  • 111
2 votes
1 answer
95 views

Dipping into sets of parallel edges in graph drawings

Given a multigraph embedded in the plane call a maximal set of parallel edges between $u,v$ such that only one of the induced faces contains nodes besides $u$ or $v$ a topologically parallel set (tell …
Hao S's user avatar
  • 111
1 vote
1 answer
75 views

Given a vertex $u$ (of bounded degree $k$) and another vertex $v$ in a planar graph, what is...

Given a vertex $u$ (of bounded degree $k$) and another vertex $v$ in a planar graph $G$, what is the smallest number of "curves" in the plane drawn from $u$ to $v$ such that no $u$--$v$ path in $G$ i …
Hao S's user avatar
  • 111
1 vote
0 answers
77 views

Is there a variant of the crossing lemma for multigraphs with arbitrary embedding?

Suppose $G$ is a graph embedded in the plane with $m=|E(G)|$ edges and $n=|V(G)|$ vertices. Suppose $\operatorname{sim}(G)$, the simplification of $G$ contains $ m' \gg 3n $ edges. Call the set of edg …
Hao S's user avatar
  • 111
1 vote
0 answers
97 views

Problem related to crossing number

Let $G$ be a graph embedded in the plane (with crossings). For $ F \subset E(G) $, denote by $c(F)$ the set of edges of $G$ that cross some edge in $F$. Denote $\delta(v)$ the set of edges with one e …
Hao S's user avatar
  • 111
1 vote
0 answers
42 views

What lower bounds are known for pair crossing number and related questions in multigraphs?

So in terms of crossing number https://arxiv.org/pdf/1808.10480 gives a lower bound of $O(e^{2.5}/n^{1.5})$ for multigraphs with no face of length 2 with no node contained inside. What do we know abo …
Hao S's user avatar
  • 111