University of Łódź

In this paper, we consider a nondifferentiable multiobjective interval-valued bilevel optimization problem where the involved functions are characterized by their tangential subdifferentials. We establish optimality conditions for this nonsmooth extremum problem by transforming its hierarchical model into a single-level one by using the optimal value reformulation. Namely, under a nonsmooth version of Zangwill’s constraint qualification, we derive necessary optimality conditions of the Karush-Kuhn-Tucker type in terms of the tangential subdifferentials of the involved functions. Further, we prove sufficient optimality conditions under the assumption that the functions involved are generalized invex functions which are characterized by their tangential subdifferentials. The applicability of the established optimality conditions is demonstrated through illustrative examples of nondifferentiable multiobjective interval-valued bilevel optimization problems.

The aim of this paper is to investigate how the presence of women on corporate boards shapes the scope of climate disclosure on energy use and greenhouse gas emissions in the context of mandatory reporting introduced by the Non-Financial Reporting Directive (NFRD). Addressing inconsistencies in prior research and the limited evidence on gender-related dynamics in compliance with mandatory disclosure, we examine whether different forms of female board representation generate heterogeneous treatment effects once the NFRD enters into force. Using a sample of 72 companies listed on the Warsaw Stock Exchange subject to the NFRD requirements, we apply a difference-in-differences design to capture firm-level variation in disclosure behavior over time. The findings show that the introduction of the NFRD does not affect all firms uniformly: Companies with a critical mass of at least three female directors or a female board chair experience significantly stronger post-NFRD increases in the scope of climate-related disclosure. These heterogeneous treatment effects suggest that numerical representation and structural power of female directors, treated independently, condition firms’ responsiveness to mandatory sustainability reporting. The results are robust to a series of additional tests, including pooled models, sector-specific subsamples, and propensity score matching.

The Nordic Seas, bounded by the North Atlantic and the Arctic Ocean, are pivotal for global ocean circulation and climate regulation. The region's unique geological features, particularly the Greenland-Iceland-Faroe (GIF) Ridge, create distinct environmental conditions characterized by varying water masses and seabed temperatures. This study investigates benthic isopod crustaceans of the Nordic Seas along a bathymetric gradient from the continental shelf to the abyss, with a particular focus on the Ægir Ridge. During the IceAGE-3 (SO276/MerMet17-06) expedition onboard RV Sonne in boreal summer 2020 samples were collected using a modified epibenthic sledge at depths ranging from 681 to 3,702 m along the ridge. These data were complemented by previously published data from the region to create a comprehensive transect spanning from the crest of the GIF Ridge to abyssal depths of the Ægir Ridge. Our results indicate that isopod diversity was highest at 400–800 m, corresponding to the thermocline, and decreases toward the abyssal Nordic Seas, likely due to the region’s energy-poor and isolated nature. Distance-based redundancy analysis (dbRDA) indicated that community composition was primarily structured by depth and bottom temperature, while other environmental variables had weaker effects. The study also underscores persistent taxonomic challenges in identifying deep-sea species, such as presence of species complexes, potentially leading to underestimated biodiversity. This highlights the pressing need for improved taxonomic resources in deep-sea biodiversity research. Overall, this research enhances our understanding of deep-sea biodiversity and sheds light on the complex interplay of environmental factors shaping these remote ecosystems.

The practice of diplomacy has been transformed by the advent of the internet and social media, which have expanded traditional diplomatic channels and enabled direct engagement with local audiences Within this context, digital public diplomacy (DPD) has become an essential tool for embassies seeking to shape narratives, foster dialogue, and strengthen international relationships. This shift has become particularly relevant in the European security environment following Russia’s invasion of Ukraine and Sweden’s subsequent accession to NATO, which has intensified Swedish–Polish strategic cooperation. The study adopts a qualitative case-study design combining conventional content analysis of 201 Instagram posts published between August 2023 and June 2024 with two semi-structured interviews conducted with embassy communication staff in 2025. The analysis identifies dominant thematic categories, communication strategies, and narrative elements and assesses their alignment with Sweden’s foreign-policy priorities and strategic narratives. The study addresses four key research questions: (1) What are the features and elements of the Embassy’s communication through social media? (2) What are the main thematic areas of its online communication? (3) To what extent is the communication tailored to the local Polish context? (4) How does the Embassy’s DPD align with Sweden’s broader foreign policy and strategic interests? By analysing both digital content and institutional perspectives, the study seeks to reveal how the Swedish Embassy in Warsaw operationalizes digital diplomacy to advance bilateral relations, foreign policy goals and contribute to Sweden’s international image. The findings indicate that the Embassy’s Instagram communication is primarily oriented toward cultural diplomacy, value promotion, and relationship-building, with comparatively increasing emphasis on hard security issues due to the changing regional security context. Addtionally, the study indicates that Instagram is used strategically to support long-term image-building and public engagement rather than short-term policy messaging. The study also finds that the Embassy’s digital communication broadly aligns with Sweden’s branding and public-diplomacy strategies.

A mathematical model of a multi-objective problem for combinatorial configurations of polypermutations is proposed, and its features are analyzed taking into account the properties of combinatorial configurations and their graphs. A new algorithm for a horizontal approach to solving such problems of finding a set of Pareto-optimal solutions is developed, based on adaptive combinatorial search and heuristic methods. The operation of the proposed algorithm is illustrated by solving a test problem. Based on numerical experiments, the effectiveness of the algorithm on Euclidean configurations of polypermutations and permutations with repetitions is justified, taking into account modern approaches in combinatorial and vector optimization.