Localized and weighted versions of extremal problems

Abstract

Malec and Tompkins (EUJC, 2023) considered the localized versions of Tur\'an-type problems, and proved a localized theorem on Erd\H{o}s-Gallai Theorem on paths. Zhao and Zhang (JGT, 2025) gave a long proof of a localized version of Erd\H{o}s-Gallai Theorem on cycles. In this paper, we consider several types of generalization of Tur\'an-type problems, that is, localized versions, weighted versions, and generalized Tur\'an-type problems, and their connectedness. We first present very short proofs for recent results of Malec-Tompkins and Zhao-Zhang, respectively. We use Small Path Double Cover Conjecture, which was proposed by Bondy (JGT, 1990) and confirmed by Hao Li (JGT, 1990), to prove a weighted localized Tur\'an-type theorem on paths. We prove localized versions of Balister-Bollob\'as-Riordan-Schelp Theorem (JCTB, 2003) on paths and Erd\H{o}s-Gallai Theorem on matchings, respectively. We show that our first localized result implies Balister-Bollob\'as- Riordan-Schelp Theorem, Erd\H{o}s-Gallai Theorem, and Malec-Tompkins Theorem on paths. Finally, we present generalized Tur\'an-style generalizations of the Malec-Tompkin's Theorem, and discuss the relationship between some previous theorems in different motivations.