Jeck Lim, Sums of linear transformations
We show that if $L_1$ and $L_2$ are linear transformations from $\mathbb{Z}^d$ to $\mathbb{Z}^d$ satisfying certain mild conditions, then, for any finite subset $A$ of $\mathbb{Z}^d$, \ This result corrects …
10 events found.
Virtual Discrete Math Colloquium
Events
-
-
Zoom ID: 870 0312 9412 (ibsecopro) [CLOSED]
-
Chengfei Xie, On the packing densities of superballs in high dimensions
Zoom ID: 870 0312 9412 (ibsecopro) [CLOSED]The sphere packing problem asks for the densest packing of nonoverlapping equal-sized balls in the space. This is an old and difficult problem in discrete geometry. In this talk, we …
-
Xizhi Liu, Hypergraph Turán problem: from 1 to ∞
Zoom ID: 870 0312 9412 (ibsecopro) [CLOSED]One interesting difference between (nondegenerate) Graph Turán problem and Hypergraph Turán problem is that the hypergraph families can have at least two very different extremal constructions. In this talk, we …
-
-
Sepehr Hajebi, Holes, hubs and bounded treewidth
Zoom ID: 869 4632 6610 (ibsdimag)A hole in a graph $G$ is an induced cycle of length at least four, and for every hole $H$ in $G$, a vertex $h\in G\setminus H$ is called a …
-
Noam Lifshitz, Product free sets in the alternating group
Zoom ID: 870 0312 9412 (ibsecopro) [CLOSED]A subset of a group is said to be product free if it does not contain the product of two elements in it. We consider how large can a product …
-
-
Lars Jaffke, Taming graphs with no large creatures and skinny ladders
Zoom ID: 869 4632 6610 (ibsdimag)We confirm a conjecture of Gartland and Lokshtanov : if for a hereditary graph class $\mathcal{G}$ there exists a constant $k$ such that no member of $\mathcal{G}$ contains a $k$-creature …
-
Akash Kumar, Random walks and Forbidden Minors
Zoom ID: 870 0312 9412 (ibsecopro) [CLOSED]Random walks and spectral methods have had a strong influence on modern graph algorithms as evidenced by the extensive literature on the subject. In this talk, I will present how …
-
Brett Leroux, Expansion of random 0/1 polytopes
Zoom ID: 870 0312 9412 (ibsecopro) [CLOSED]A conjecture of Milena Mihail and Umesh Vazirani states that the edge expansion of the graph of every $0/1$ polytope is at least one. Any lower bound on the edge expansion gives …
-
Raphael Steiner, Congruence-constrained subdivisions in digraphs
Zoom ID: 869 4632 6610 (ibsdimag)I will present the short proof from that for every digraph F and every assignment of pairs of integers $(r_e,q_e)_{e\in A(F)}$ to its arcs, there exists an integer $N$ such …
-
-
Dömötör Pálvölgyi, C-P3O: Orientation of convex sets and other good covers
Zoom ID: 870 0312 9412 (ibsecopro) [CLOSED]We introduce a novel definition of orientation on the triples of a family of pairwise intersecting planar convex sets and study its properties. In particular, we compare it to other …