## 4 Discussion  
The gPLC model consolidates the wide variety of lifecycle models, which are created from single-disciplinary, integrative or cross-cutting perspectives. While generalization always implies an abstraction of specificities, the gPLC covers all highlighted aspects. It is focused on value creation (Finding 1) but with a scope on both intrinsic Product Creation (value for consumers/users) and CE (expanded value for the enterprise). The cycle metaphor is used to emphasize circularity of material and information, while the Product Creation process is highlighted with its problem-solving, goal-oriented characteristics (Finding 2). Product classes are used as the primary viewpoint, but the instantiation of single product instances is introduced as an essential secondary viewpoint (Finding 3). In the gPLC visualization, it is presented as a lateral view of the Product Creation process. Hence, treatment of instances by users and material flow can be analyzed within the overall context of the gPLC. Besides logical dependencies, temporal alignment across phases and disciplines/domains is reflected (finding 4). Information circularity is hardly recognized in other Product Lifecycle models. In the gPLC, however, it is elaborated on the same level of detail as material circularity (Finding 5). Information refers to product class, single instances or aggregated instances. Based on this differentiation, cycles are possible between all gPLC phases. Both differences in realization and integrative aspects are incorporated (Finding 6). Regarding differences in realization, this covers the preparation of servicing and the production of material core products. Integrative aspects are concerned with utilizing assets and material to produce product instances, deploying software on core product platforms, etc. When doing so, the temporal synthesis recognizes flexibility in between phases and across disciplines (Finding 7). For instance, software sub-systems might follow more cycles in terms of versions than a service that is related to it. While preparation of a service as part of a product-service system is more or less finalized after realization, realization and operation of material products overlap until production is discontinued. Circularity is understood as the main driver of economy in the future, highlighting both information and material (Finding 8). CE is applied to both categories: besides material circularity, CE is also combined with data economy. Based on the differentiation of product class and instances, it is now possible to include the economic view on lifecycle phases into the gPLC (Finding 9). This strengthens the support for CE ambitions. The gPLC model is a key to frame planning, design and engineering of circular business models. It is coherent with the perspective of [20], valuing early Product Creation phases as a key to achieve closed loops. While they focus on design skills necessary to create products for closed loops, the gPLC guides the perspective of skilled engineers. It is compatible with established engineering methodologies in different disciplines. It serves as a generic model to evaluate and extend Design-for-X (DfX) purposes, fostering Circular Economy adoption acknowledged by [24] and specifically detailed by [109]. Relevant DfX purposes are mainly design evaluation, design decision support and design knowledge management. The intention is to support even design as a driver of CE transition. Therefore, the gPLC extends the focus on the Product Lifecycle phase of VDI 2221 [28] regarding inter-disciplinarity, product types from material products to product-service systems and the CE perspective. The alignment of Product Creation phases is meant as a framework to adopt procedural models, such as the V-model for mechatronic and cyber-physical systems [110]. Engineering-specific types of products, such as pure service/software bundles, can be supported by reduction in the gPLC.