This postdoctoral position at the Faculty of Philosophy, University of Warsaw, is part of the National Science Center Weave-Unisono project 'Structural complexity measures for foundational theories,' co-run with the Technical University of Vienna. The project aims to analyze the Scott ranks of models of foundational mathematical theories, including Peano Arithmetic (PA), Second-Order Arithmetic, and Zermelo-Fraenkel Set Theory (ZF), as well as their subsystems. The Scott rank is a measure of the complexity of countable models in infinitary logic, and the project seeks to determine Scott functions for these theories and their completions, as well as their general properties. The research requires expertise in mathematical logic, including computability theory, descriptive set theory, nonstandard models, and reverse mathematics. The successful candidate will be assigned specific research tasks based on their background and preferences and will collaborate closely with the Principal Investigator, Dr. Mateusz Łełyk, and the interdisciplinary team, including the group of Dino Rossegger at the Technical University of Vienna. Responsibilities include conducting research, participating in team meetings, publishing results in international journals, presenting at conferences, and helping organize project-related events. The position is for 24 months, full-time, with no mandatory teaching duties but opportunities for teaching experience. The annual gross remuneration is PLN 140,000, with a monthly salary of about PLN 8,900 plus a '13th' salary, and additional funds for conferences, literature, and a work laptop. Applicants must hold a PhD in philosophy, logic, mathematics, or theoretical computer science, obtained no earlier than 12 years before employment, and must demonstrate advanced research ability in relevant areas of mathematical logic. Advanced English proficiency (C1/C2) is required. The PhD must be from an institution other than University of Warsaw, or the candidate must have completed a postdoctoral fellowship of at least 10 months at another institution and country. Additional advantages include scientific experience abroad, research achievements, and organizational or science popularization experience. The University does not provide accommodation. The application process involves submitting a set of documents electronically, including a questionnaire, personal data information, PhD diploma, proof of English proficiency, cover letter, academic writing sample, and 1-2 letters of recommendation. The selection process includes formal evaluation, document assessment, and interviews conducted remotely in English. The competition will be resolved by January 27th, 2026, and candidates will be informed by email.