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The paper presents LIFREM (Loops Including FREight Model), a model framework for improving the representation of maritime freight transport in large-scale freight transport models by integrating loops, cargo consolidation, and backhaul operations. Many large-scale freight models, such as the Swedish national freight transport model Samgods, calculate annual goods flows across different transport modes by minimizing firm-to-firm costs. These models generally restrict vehicles and vessels to direct routes, excluding the multi-stop routing patterns typical of maritime operations. This limitation reduces their ability to capture complex maritime dynamics such as port loops, consolidation, and backhaul. Using concepts from operational research and liner shipping network design, LIFREM uses a mixed-integer linear programming (MILP) framework to optimize freight assignments and incorporate loops and backhaul, thereby extending the representation of maritime transport in large-scale freight transport models and improving the representation of economies of scale in maritime transport. A case study of forest product exports from Northern Sweden illustrates how the inclusion of loops and backhaul in the modeled system can reduce transport costs and shift freight towards larger vessels, producing routing patterns qualitatively consistent with observed maritime transport structures in the Baltic Sea. The results also indicate that modal shifts may be non-linear, with transport modes remaining stable until threshold effects are reached. Computational scaling experiments assess the feasibility of applying the MILP formulation as a complementary module in large-scale freight transport models. The paper concludes by discussing limitations, computational tradeoffs, and possibilities for modular integration of the framework into large-scale freight transport models.

We argue for more widespread use of manifold-like polyfolds (M-polyfolds) as differential geometric objects. M-polyfolds possess a distinct advantage over differentiable manifolds, enabling a smooth and local change of dimension. To establish their utility, we introduce tensors and prove the existence of Riemannian metrics, symplectic structures, and almost complex structures within the M-polyfold framework. Drawing inspiration from a series of highly acclaimed papers by László Lempert, we are laying the foundation for advancing geometry and function theory in complex M-polyfolds.

Travel survey data from Umeå, Sweden, show that lower winter bicycle share is part of a broader seasonal reallocation of urban travel. Cycling declines sharply in winter, while walking and bus shares increase. The accompanying mode-share changes differ across groups: men show larger increases in walking, women show larger increases in bus use, and work and education trips retain higher winter bicycle shares than shopping and leisure trips. These findings suggest that winter cycling should be analyzed together with walking and public transport, and that seasonal mobility patterns vary by gender and trip purpose.

This study investigates the critical transition from secondary to tertiary mathematics education, focusing on students’ challenges and the impact of curriculum reforms in Sweden. Through an analysis of diagnostic test scores and admission data from Umeå University over the period 2006–2021, we examine the evolving mathematical competencies of incoming engineering students and the broader implications of these shifts for educational policy and student preparedness for higher education. Our findings indicate a significant improvement in students’ mathematical readiness in the latter years of the study, correlating with the implementation of curriculum changes and variations in admission statistics. This research documents the positive outcomes of these educational reforms on student preparedness. It places these findings within a global context, highlighting the universal challenges and responses in mathematics education transitions. The study underscores the complex dynamics of the secondary-tertiary transition and provides valuable insights into the specific mathematical areas where students have shown varying degrees of improvement.

The ψ(x)-function, which solves the equation x = sinh(aw)ew for 0 < a < 1, has a natural connection to the renowned Lambert W function and also physical relevance through its connection to the Lenz–Ising model of ferromagnetism. We provide a detailed analysis of its complex branches and construct Riemann surfaces from these under various conditions of a, unveiling intriguing new links to the Lambert W function.

This study extends the celebrated volume-capacity estimates of Dinew and Kołodziej, providing a foundation for examining the regularity of solutions to boundary value problems for complex Hessian equations. By integrating the techniques established by Dinew and Kołodziej and incorporating recent advances by Charabati and Zeriahi, we demonstrate the continuity of the solutions.

Sammanfattning. Denna studie utvidgar det välkända volym-kapacitetsestimatet av Dinewoch Kołodziej och lägger därmed grunden för att undersöka regulariteten hos lösningar till randvärdesproblemför komplexa Hessianska ekvationer. Genom att kombinera de metoder som utvecklatsav Dinew och Kołodziej med nyligen gjorda framsteg av Charabati och Zeriahi, visar vi kontinuitethos lösningarna.

Addressing the intricate challenges in plane elasticity, especially with non-vanishing traction and complex geometries, requires innovative methods. This paper offers a novel approach, drawing inspiration from the Neumann problem for the inhomogeneous Cauchy-Riemann equations. Our method applies to domains conformally equivalent to a unit disk or an annulus, focusing on deriving explicit solutions for the displacement field rather than the stress tensor, which distinguishes it from most traditional approaches. We explore solutions for specific classical cases to demonstrate its efficacy, such as a cardioid domain, a ring domain with a shifted hole, and a gear-like structure. This work enhances the toolkit for researchers and practitioners tackling isotropic planar elastostatic challenges with a unified and flexible approach.

In this paper, we extend the concept of finite entropy measures in Kähler geometry. We define the finite p-entropy related to ω-plurisubharmonic functions and demonstrate their inclusion in an appropriate energy class. Our study is anchored in the analysis of finite entropy measures on compact Kähler manifolds, drawing inspiration from fundamental works of Di Nezza, Guedj, and Lu [Comment. Math. Helv. 96 (2021), pp. 389–419]. Utilizing a celebrated result by Darvas [Adv. Math. 285 (2015), 182–219; Math. Ann. 389 (2024), pp. 427–450] on the existence of a Finsler metric on the energy classes, we conclude this paper with a stability result for the complex Monge-Ampère equation.

This study examines geodesics and plurisubharmonic envelopes within the Cegrell classes on bounded hyperconvex domains in Cn. We establish that solutions possessing comparable singularities to the complex Monge–Ampère equation are identical, affirmatively addressing a longstanding open question raised by Cegrell. This achievement furnishes the most general form of the Bedford–Taylor comparison principle within the Cegrell classes. Building on this foundational result, we explore plurisubharmonic geodesics, broadening the criteria for geodesic connectivity among plurisubharmonic functions with connectable boundary values. Our investigation also delves into the notion of rooftop envelopes, revealing that the rooftop equality condition and the idempotency conjecture are valid under substantially weaker conditions than previously established, a finding made possible by our proven uniqueness result. The paper concludes by discussing the core open problems within the Cegrell classes related to the complex Monge–Ampère equation.

Ingenjörers arbete präglas allt oftare av komplexa hållbarhetsutmaningar där ekonomiska, miljömässiga och sociala mål måste vägas samman. Många av dessa frågor är så kallade wicked problems: otydligt avgränsade, förknippade med motstridiga intressen och osäker kunskap, samt föränderliga över tid. För att mötadetta behov har vi utvecklat kursen Optimering för hållbarhet (planerad start våren2026), riktad till yrkesverksamma ingenjörer, analytiker och beslutsfattare som arbetar med hållbarhetsfrågor. Kursen förenar avancerad teori inom optimering och beslutsteori med praktiska tillämpningar kopplade till deltagarnas egna verksamheter. Upplägget kombinerar föreläsningar som ger teoretisk grund med ett strukturerat projekt där deltagarna stegvis utvecklar och analyserar en hållbarhetsrelaterad frågeställning. Centrala teman är hantering av risk och osäkerhet, framtidsscenarier och målkonflikter i komplexa beslut. Deltagarna arbetar med metoder som multimåloptimering, Monte Carlo‑simuleringar, scenarioanalyser, Pareto‑fronter och skuggpriser. Resultat diskuteras i seminarier och knyts till reflektion kring metodval och beslutsunderlag, med kontinuerlig återkoppling för att stödja lärandet. Den pedagogiska designen vilar på evidensbaserade principer som betonar vägledning i undervisningen och betydelsen av faktakunskap som grund för förståelse och problemlösning. Genom att kombinera strukturerad undervisning med arbetsintegrerat projektarbete och kollegiala samtal skapas en lärmiljö där teori omsätts i praktik och deltagarnas erfarenheter blir en aktiv del av innehållet. Kursen förväntas ge direkt tillämpbara verktyg för att integrera hållbarhetsperspektiv i organisationers beslutsprocesser och stärka deltagarnas förmåga att agera i komplexa, osäkra och målkonfliktfyllda miljöer.