PreprintCC BY 4.0arXiv
The extremal cases of the Erd\H os--Sós conjecture
Abstract
The Erd\H os--Sós conjecture states that every n-vertex graph G with more than (k−2)n/2 edges contains every k-vertex tree. We solve the extremal cases of this conjecture, showing that for some fixed μ>0, the conjecture holds for each G that minimally satisfies the assumptions of the conjecture and has a subgraph~H of minimum degree δ(H)≥ (1−μ)k. In our proof, we mainly have to deal with H taking two different shapes: either H is close to the complete graph Kk or H is close to the complete bipartite graph Kk,k.
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BibTeX
@misc{reed2026extremal,
title = {{The extremal cases of the Erd\H os--Sós conjecture}},
author = {Bruce Reed and Maya Stein},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.05411},
eprint = {2609.05411},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.05411},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The extremal cases of the Erd\H os--Sós conjecture
AU - Bruce Reed
AU - Maya Stein
PY - 2026
DA - 2026/09/08
PB - arXiv
DO - 10.48550/arxiv.2609.05411
UR - https://arxiv.org/abs/2609.05411
AB - The Erd\H os--Sós conjecture states that every n-vertex graph G with more than (k−2)n/2 edges contains every k-vertex tree. We solve the extremal cases of this conjecture, showing that for some fixed μ>0, the conjecture holds for each G that minimally satisfies the assumptions of the conjecture and has a subgraph~H of minimum degree δ(H)≥ (1−μ)k. In our proof, we mainly have to deal with H taking two different shapes: either H is close to the complete graph K_k or H is close to the complete bipartite graph K_k,k.
ER -