Abstract
We study a generalization of the Turán problem in random graphs. Given graphs T and H, let ex(G(n,p),T,H) be the largest number of copies of T in an H-free subgraph of G(n,p). We study the threshold phenomena arising in the evolution of the typical value of this random variable, for every H and every 2-balanced T. Our results in the case when m2(H) > m2(T) are a natural generalization of the Erdős-Stone theorem for G(n,p), proved several years ago by Conlon-Gowers and Schacht; the case T = Km was previously resolved by Alon, Kostochka, and Shikhelman. The case when m2(H) ≤ m2(T) exhibits a more complex behavior. Here, the location(s) of the (possibly multiple) threshold(s) are determined by densities of various coverings of H with copies of T and the typical value(s) of ex(G(n,p),T,H) are given by solutions to deterministic hypergraph Turán-type problems that we are unable to solve in full generality.
| Original language | English |
|---|---|
| Pages (from-to) | 283-305 |
| Number of pages | 23 |
| Journal | Random Structures and Algorithms |
| Volume | 56 |
| Issue number | 2 |
| DOIs | |
| State | Published - 1 Mar 2020 |
Keywords
- Turán's theorem
- random graphs
- thresholds
All Science Journal Classification (ASJC) codes
- Software
- Applied Mathematics
- General Mathematics
- Computer Graphics and Computer-Aided Design