Altun, IshakGençtürk, İlkerErduran, Ali2025-01-212025-01-2120231392-5113https://doi.org/10.15388/namc.2023.28.33436https://hdl.handle.net/20.500.12587/23532In this paper, we introduce two new properties to the Q-function, called as the 0-property and the small self-distance property, which is frequently used in studies of fixed point theory in quasimetric spaces. Then, with the help of Q-functions having these properties, we present some fixed point theorems for Preši?-type mappings in quasimetric spaces. Finally, we state a theorem for the existence and uniqueness of the solution to a boundary value problem for (p, q)-difference equations to demonstrate the applicability of our theoretical results, which we support with an example. © 2023 The Author(s).eninfo:eu-repo/semantics/openAccess(p,q)-difference equation; fixed point; Preši?-type mapping; Q-function; quasimetric spaceArticle2861089110210.15388/namc.2023.28.334362-s2.0-85176216618Q1