Program

Sun, Oct 4 (Room: Torremolinos C)

Session 1: Foundations of Multi-Level Modeling
9:15 – 10:30

Chair: Pierre Maier
9:15 Welcome and Introduction
9:20
Modeled Field Semantics: Making Field Behavior Explicit in Multi-Level Modeling
Gergely Mezei, Ferenc Attila Somogyi and Gergely Gembela
Abstract: Multi-level modeling provides established mechanisms for describing how fields characterize elements across multiple abstraction steps. Potency-based approaches are especially useful when the intended depth of characterization is known and can be expressed directly in the modeling language. This paper presents a different solution, referred to as Modeled Field Semantics (MFS). Instead of defining field behavior only as a built-in language mechanism, MFS represents certain aspects of field behavior explicitly in the model.

The motivation for MFS comes from cases where field behavior is not limited to assigning a value at a predetermined abstraction depth. A value may be interpreted differently by classifier-objects and instance-objects, and the differences may also become part of the field structure itself, for example when a general field later continues as several distinct fields representing different roles. In MFS, such decisions are not treated only as consequences of predefined field semantics, but can be expressed in the model through explicit field relationships, assignment rules, and value access operations.

MFS treats selected aspects of field behavior as part of the modeled semantics. Field lineage, value-assignment rules, getter and setter behavior, and their configuration can be represented explicitly instead of being fully pre-encoded as one fixed language semantics. The result is a way to describe field semantics in which structural behavior and value interpretation remain explicit, adjustable, and subject to validation within the model.
9:55
Deep Reactions: Realizing and Evaluating Consistency Preservation for Multi-Level, Multi-View Models
Annika Kienle, Arne Lange, Thomas Weber, Lars König, Nathan Hagel and Erik Burger
Abstract: In view-based development, consistency plays a central role across concrete models. Consistency can be achieved automatically through consistency-preservation rules defined, for instance, in a change-driven language such as the Reactions language of the Vitruvius framework. This language, however, assumes the classical two-level architecture with a strict separation of type and instance level and can therefore only handle multi-level models through their generic linguistic structure. This forces domain questions to be encoded as not statically typed string operations on infrastructure metaclasses. Based on a previously published vision, this paper presents the Deep Reactions language. It lets a stable region of a deep model serve as an ontological metamodel, over which ontological types and features can be referenced directly and deep characterization through offspring-aware triggers can be exploited. Building on the stable code generation of the original Reactions language, a pre-processing step first transforms Dep Reactions into regular Reactions which ensures compatibility with existing implementations. Our evaluation shows that the number of referenced metamodels and the token count can be reduced while removing 83% of statically unvalidated type references.
10:30 Coffee Break

Session 2: Practical Considerations of Multi-Level Modeling
11:00 – 12:45

Chair: Gergely Mezei
11:00
Multi-Level Modeling as the Execution Substrate of a No-Code Platform: An Industrial Experience with Metada
Petr Smolík
Abstract: We report on an industrial realization of multi-level modeling (MLM): Metada, a commercial enterprise no-code application platform whose runtime interprets models directly rather than generating code. Its foundation is a two-layered meta-architecture — RBSM, a linguistic meta-metamodel offering one deep instantiation relationship with per-property propagation controls, and Meta4, an ontological metamodel of concepts and typed properties built on RBSM. We claim no new multi-level concepts: RBSM’s primitives align with the orthogonal classification architecture, characterization potency, and the durability/mutability vitality properties established in prior work. Our contribution is an engineering and experience one — how these concepts behave once they become the substrate of a persisted, multi-tenant business-application runtime, integrated end-to-end with storage, an operational constraint layer, and model-driven user interfaces. We use a published MLM challenge domain as a worked, executable, test-covered example, contrast our engineering decisions with five research approaches (DeepTelos, DMLA, FMMLx, DLM, Melanee), and draw on three production and reference models — an ArchiMate metamodel reused by folder inheritance, a multi-tenant ticketing platform, and a 6000- product banking catalog that instantiates down to a client-holding level (a three-level chain). We distill lessons, most notably that deep values are inherited by derivation, caching, and search-indexing rather than duplication, and that integrity is best expressed as platform-native operations rather than a declarative constraint language.
11:35
Transforming a large Flat Model into a Multi-Level Model: A Retrospective Case Study
Ulrich Frank
Abstract: This paper presents a case study comprising the analysis and transformation of a large flat object model into a multi-level model. To support the transformation, a corresponding method is introduced and applied. The resulting multi-level model is evaluated against the original requirements as well as with regard to further aspects.
12:10
Property-Precedence Analysis for Model Deepening
Pierre Maier
Abstract: Despite widely accepted prospects, multi-level modeling remains sparsely adopted in industry. Model deepening –, i.e., the re-engineering of flat representations into multi-level models – has the potential to facilitate the industrial adoption of multi-level modeling by transforming models and representations of information systems an organization already possesses. Prior research has focused primarily on transformation operations; comparatively little attention has been devoted to the preceding analysis problem of identifying beneficial model-deepening transformations. Existing approaches typically rely on type-level heuristics such as naming patterns, aggregation relationships, or association multiplicities. Since these heuristics suggest multi-level hierarchies based on modeling choices and conventions rather than the represented instance population, they cannot reliably distinguish genuine classification levels from incidental modeling choices.

This paper proposes property-precedence analysis, an instance-driven approach to conduct model-deepening analysis. Building upon Bunge's ontological notion of property precedence, the proposed approach uncovers possible multi-level hierarchies by analyzing the distribution of property values across model instances rather than relying on type-level heuristics. The analysis is implemented in the prototype ModelDeepener for the MLM language FMMLx and demonstrated using two example models involving associations and attributes. Several challenges in property-precedence analysis for model deepening remain, such as handling conflicting precedence relations and naming newly suggested classes. Further research should investigate to what degree the identified challenges may be counteracted and how property-precedence analysis may be complemented with type-level heuristics for model deepening.
12:45 Lunch

Session 3: Support for Creating and Managing Multi-Level Models
14:30 – 15:45

Chair: Georg Grossmann
14:30
Assessing Capabilities of Large Language Models for Multi-Level Modeling
Arianna Fedeli, Ludovico Iovino, Maria Teresa Rossi and Adrian Rutle
Abstract: Large Language Models (LLMs) are increasingly being explored in Model-Driven Engineering as assistants for generating, transforming, and evolving modeling artifacts from natural language descriptions. Existing work, however, has mainly focused on traditional two-level modeling settings, while the applicability of LLMs to multilevel modeling remains largely unexplored. Multilevel modeling introduces specific challenges, including reasoning across multiple abstraction levels, handling deep instantiation, preserving cross-level consistency, and distinguishing between types, instances, and linguistic classifications.

This paper investigates the capabilities and limitations of LLMs in supporting multilevel modeling tasks from natural language descriptions. We propose a scenario-based evaluation framework that combines two representative case studies from the MULTI challenge series with a conventional two-level modeling benchmark. The framework evaluates LLMs across six representative MLM tasks, covering hierarchy navigation, additive and subtractive model evolution, structural modifications, instance generation, and complete hierarchy synthesis. The results show that LLMs can support exploratory MLM tasks, but their outputs remain candidate artifacts that require expert validation, especially when correctness depends on cross-level reasoning and the preservation of consistency.
15:05
Managing Model Complexity: A Segment-Based Approach
Thomas Kühne and Pierre Maier
Abstract: Multi-level modeling (MLM) is typically characterized as minimizing accidental complexity. We observe that MLM levels also aid in managing essential model complexity by separating and organizing model content based on the domain classification level it represents. Building on this insight, we generalize the notion of a level—and previously recognized pluralities of elements, e.g., those contained in packages—to that of a model segment. In addition to solution-based segments, we recognize domain-induced segments, such as domain diversity allowing semantic information to be represented in models that was previously lost to mapping different modeler intents to the same modeling constructs. These new, semantically relevant, model segments support better model navigability and aid model understanding by facilitating the isolation of particular model aspects. Crucially, all model segments are subject to being represented by proxies, thus enabling a significant reduction of first-contact model complexity. We posit that introducing segments for managing model complexity has the potential to lower the threshold of MLM adoption due to its ability to counteract the often-held perception of MLM models being complex.
15:45 Coffee Break

Session 4: Emerging Application Areas of Multi-Level Modeling
16:15 – 17:35

Chair: Ulrich Frank
16:15
Deep Instantiation Meets Dependent Typing – The Potential of Coding Potency in Potent Type Systems
Friedrich Steimann and Ralf Lämmel
Abstract: Multi-level modelling (MLM) extends conventional modelling by allowing classification hierarchies that span more than two levels, enabling concepts such as deep instantiation and level-crossing relationships. While several formal foundations for MLM have been proposed, the potential of contemporary dependent type systems as a semantic basis has received comparatively little attention. This paper therefore explores the idea of encoding multi-level models in the type systems of languages such as Scala, Lean, and Haskell, which feature dependent types, type families, and other advanced typing constructs. Although we limit ourselves to a simple setup of deep instantiation here, our findings suggest that this idea may indeed be valuable for exploring the design space of MLM languages.
16:35
Multi-Level Modeling for Interactive Scene Description and Content Creation
Gergely Gembela, Gergely Mezei and Ferenc Attila Somogyi
Abstract: Multi-level modeling (MLM) approaches and frameworks are reaching a stage where research and development of both conceptual frameworks and tooling would greatly benefit from feedback and experience from real-world use cases and industrial applications. MLM-based solutions could address the ongoing challenge of maintaining flexibility, full control, and semantic integrity throughout the development process of video games, as players expect increasingly vast, unique, and highly detailed environments.

In this position paper, we propose the concept of a multi-level model-based framework: Multi-Layer Content Model (MLCM), that utilizes MLM concepts to describe, store, and transport Digital Content Creation (DCC) assets, serving as a universal interconnect between DCC tools, game engines, and other DCC-related tools. MLCM also has potential to serve as a data source for both traditional and AI-based Procedural Content Generation (PCG) tools. Using MLCM, structural, behavioral, and generative descriptions are integrated into a single model, supporting iterative development, modular extension, and long-term maintainability. Beyond serving as a compact representation of generative parameters and rules, MLCM facilitates verification of model elements and, potentially, the resulting content, while also serving as a prime case study for the industrial application of MLM.
16:55
Multi-Level Modeling Pressure in the FSL Ontology – When OWL Punning Is Not Enough
Ralf Lämmel and Friedrich Steimann
Abstract: The ‘Foundations of Software Languages’ (FSL) ontology integrates software languages, tools, artifacts, concepts, technological spaces, and engineering activities. FSL features types of resources that must be treated both as objects of discourse and as classifiers, for example, when modelling artifact kinds or language concepts. FSL leverages OWL 2 punning as a pragmatic encoding for such dual roles, thereby serving as a case study for a domain ontology that could benefit from proper multi-level modelling support.
17:15
Going beyond structure – Can Dynamic Multi-Level Algebra Support Multi-Level Simulation?
Sebastian Weber, Thomas Weber, Arne Lange, Jörg Henß and Robert Heinrich
Abstract: Multi-level simulation (MLS) combines simulation models that differ in abstraction, resolution, timing, or computational cost. This makes MLS attractive for complex systems, but it also creates recurring problems: simulation artefacts must be selected, coupled, and exchanged without losing semantic compatibility. At the same time, the word “level” has different meanings in MLS and in multi-level modeling (MLM). Treating simulation resolution levels as ordinary MLM classification levels therefore risks confusing refinement, instantiation, specialization, and simulator coupling. This position paper examines Dynamic Multi-Level Algebra (DMLA) as a modeling basis for MLS compatibility. We argue that DMLA should be investigated not as a direct encoding of MLS levels, but as a level-blind, refinement-based modeling formalism for explicitly representing simulation artefacts, simulator capabilities, compatibility constraints, and validation operations. An ECU software architecture example illustrates how DMLA-style validation can expose missing inputs, semantic mismatches, and unjustified simulator switches. From selected MLS and DMLA literature, we condense recurring challenges into six modeling needs and identify where DMLA can address them and where further work is required.
17:35 Closing Day 1

Mon, Oct 5 (Room: Mediterraneo A)

Session 5: Keynote
9:15 – 10:30

Chair: Arne Lange
9:15
Keynote: Models That Must Live: Metamodeling Challenges in MBSE Tool Practice
Clemens Reichmann
Abstract: Industrial MBSE tools are subject to a permanent tension: simplicity versus expressiveness, short-term modelability versus long-term consistency. This keynote offers a practitioner's perspective on metamodel development, drawing on experience with PREEvision, a development environment for automotive E/E systems. It addresses questions that arise repeatedly in day-to-day tooling work: What drives the complexity of a metamodel? How can modeling layers be kept consistent when partial models are versioned and evolved independently? The keynote discusses where the classical two-level paradigm reaches its limits – and what impulses multi-level modeling can offer for industrial practice.
10:30 Coffee Break

Session 6: MULTI Vector Industry Challenge and Closing Discussion
11:00 – 12:45

Chair: Arne Lange
11:00
MULTI Vector Industry Challenge
Arne Lange, Clemens Reichmann, Thomas Kühne, Pierre Maier and Thomas Weber
Abstract: The MULTI workshop series has set a number of multi-level modeling challenges, each designed to allow competing multi-level modeling approaches to demonstrate their capabilities and/or to tease out their limitations. The challenges, therefore, have been serving a three-fold purpose: First, they have allowed technologies to demonstrate their abilities. Second, they have pointed out where technologies still fall short of providing optimal modeling support. Third, they have provided a basis for comparing competing technologies, often revealing the trade-offs implied by certain design choices. The MULTI Vector Industry Challenge described in this paper is the fifth installment in this series. It is unique among the existing challenges in that it has been developed in collaboration with the industry partner Vector and is directly inspired by a respective real-world modeling challenge.
11:15
Poster Session MULTI Vector Industry Challenge
  • Contractual Type-Square Pattern and Its Lack of Necessity in DLMA [Poster]
    Áron Furmann, Gergely Gembela, Ferenc Attila Somogyi, Gergely Mezei and Dániel Palatinszky
  • A PAMoLa Solution to the MULTI 2026 Vector Industry Challenge [Poster]
    Shilpi Gupta, Mohammad Sadeghi, Monalisha Ojha and Colin Atkinson
  • Ensuring Consistency via Deep Composition Semantics [Poster]
    Thomas Kühne and Arne Lange
  • An Algorithmic Solution to the Vector Challenge [Poster]
    Arne Lange and Romain Pascual
  • Native Deep Instantiation for Automotive Connector Catalogs on the Metada No-Code Platform [Poster]
    Petr Smolík
12:00 Future of MULTI: Closing Discussion

Keynote

Clemens Reichmann
Models That Must Live: Metamodeling Challenges in MBSE Tool Practice

Industrial MBSE tools are subject to a permanent tension: simplicity versus expressiveness, short-term modelability versus long-term consistency. This keynote offers a practitioner's perspective on metamodel development, drawing on experience with PREEvision, a development environment for automotive E/E systems. It addresses questions that arise repeatedly in day-to-day tooling work: What drives the complexity of a metamodel? How can modeling layers be kept consistent when partial models are versioned and evolved independently? The keynote discusses where the classical two-level paradigm reaches its limits – and what impulses multi-level modeling can offer for industrial practice.

Clemens Reichmann

Clemens Reichmann is Principal Research Advisor in the Predevelopment & Innovation division at Vector Informatik GmbH in Karlsruhe, where he has worked for 20 years. Prior to joining Vector, he co-founded aquintos GmbH, a spin-off of the Karlsruhe Institute of Technology (KIT), which he grew as managing director to a team of up to 40 employees. At Vector, he spent over a decade as Technical Director and Head of Strategic Product Management, responsible for the development and product management of PREEvision, an industrial development environment for automotive E/E systems. Today he shapes the strategic evolution of MBSE methods and tool ecosystems and explores how AI can process, transform, and reason about engineering models. He has been a lecturer in Software Engineering at KIT since 2005 and is a member of the advisory board of the Vector Foundation.