Resumen: It is well known that the lack of information about certain variables necessary for the description of a dynamical system leads to the introduction of historical dependence (lack of Markovian character of the model) and noise. Traditionally, scientists have made up for these shortcomings by designing phenomenological variables that take into account this historical dependence (typically, conformational tensors in fluids). Often these phenomenological variables are not easily measurable experimentally. In this work we study to what extent Transformer architectures are able to cope with the lack of experimental data on these variables. The methodology is evaluated on three benchmark problems: a cylinder flow with no history dependence, a viscoelastic Couette flow modeled via the Oldroyd-B formalism, and a non-linear polymeric fluid described by the FENE model. Our results show that the Transformer outperforms a thermodynamically consistent, structurepreserving neural network with metriplectic bias in systems with missing experimental data, providing lower errors even in low-dimensional latent spaces. In contrast, for systems whose state variables can be fully known, the metriplectic model achieves superior performance. Idioma: Inglés DOI: 10.1016/j.jnnfm.2026.105601 Año: 2026 Publicado en: JOURNAL OF NON-NEWTONIAN FLUID MECHANICS 349 (2026), 105601 [13 pp.] ISSN: 0377-0257 Financiación: info:eu-repo/grantAgreement/ES/MICINN/PID2023-147373OB-I00 Financiación: info:eu-repo/grantAgreement/ES/MTFP/TSI-100930-2023-1 Tipo y forma: Article (Published version) Área (Departamento): Área Mec.Med.Cont. y Teor.Est. (Dpto. Ingeniería Mecánica)