CC BY-NC 4.0Rehm, GeorgGeorgRehmGalanis, DimitriosDimitriosGalanisLabropoulou, PennyPennyLabropoulouPiperidis, SteliosSteliosPiperidisWelß, MartinMartinWelßUsbeck, RicardoRicardoUsbeckKöhler, JoachimJoachimKöhlerDeligiannis, MiltosMiltosDeligiannisGkirtzou, KaterinaKaterinaGkirtzouFischer, JohannesJohannesFischerChiarcos, ChristianChristianChiarcosFeldhus, NilsNilsFeldhusMoreno-Schneider, JuliánJuliánMoreno-SchneiderKintzel, FlorianFlorianKintzelMontiel, ElenaElenaMontielDoncel, Víctor RodríguezVíctor RodríguezDoncelMcCrae, John P.John P.McCraeLaqua, DavidDavidLaquaTheile, Irina PatriciaIrina PatriciaTheileDittmar, ChristianChristianDittmarBontcheva, KalinaKalinaBontchevaRoberts, IanIanRobertsVasiljevs, AndrejsAndrejsVasiljevsLagzdins, AndisAndisLagzdins2022-03-1417.12.20202020https://publica.fraunhofer.de/handle/publica/40960010.24406/publica-fhg-409600With regard to the wider area of AI/LT platform interoperability, we concentrate on two core aspects: (1) cross-platform search and discovery of resources and services; (2) composition of cross-platform service workflows. We devise five different levels (of increasing complexity) of platform interoperability that we suggest to implement in a wider federation of AI/LT platforms. We illustrate the approach using the five emerging AI/LT platforms AI4EU, ELG, Lynx, QURATOR and SPEAKER.enLR Infrastructures and ArchitecturesLR National/International Projectstoolssystemsapplicationsweb services621005006629006conference paper