A binary relation where the subject entity includes the object entity within its spatial, temporal, structural, or conceptual extent. contains a unit is a standardized quantity that is used as a reference for a particular quantity. unit is referred to in is relation between an object that is the subject of an information object. is referred to in A quantity is an information object that represents the magnitude (and unit) of an object or process. quantity has item is a relation between an item and the collection in which it contained. is item in Duration is a temporal quantity that represents the extent or (non-negative) amount of time that elapses between two temporal points, typically the start and end of a time interval. duration A binary relation where the object entity includes the subject entity within its spatial, temporal, structural, or conceptual extent. is in A relation in which one process occurs after to another process. is preceded by an end time is a time instant at the end of a process/time interval. end time existsAt a relation between any thing and the time in which it occurs at. at time has value is the (only) data type attribute to store the values of information objects. has value A relation in which one process occurs prior to another process. precedes SULO Michel Dumontier, Remzi Çelebi, Komal Gilani, Isabelle de Zegher, Katerina Serafimova, Catalina Martínez Costa and Stefan Schulz. SULO - a simplified upper-level ontology. Proceedings of the Joint Ontology Workshops (JOWO) - Episode XI: The Sicilian Summer under the Etna, co-located with the 15th International Conference on Formal Ontology in Information Systems (FOIS 2025), September 8-9, 2025, Catania, Italy 2024-11-11 2025-07-11 2025-11-20 Simplified Upper Level Ontology sulo The Simplified Upper Level Ontology (SULO) is ontology with a minimal set of classes and relations to guide the development of a personal health knowledge graph. Simplified Upper Level Ontology 0.2.9 This work is partially supported by the AIDAVA project (GA 101057062), as part of the European Union's Horizon Europe research and innovation programme. active refers to is a binary relation between an information object and any other object that it mentions, describes, represents, encodes, or otherwise provides information about. refers to A feature is any characteristic that stems from the intrisinc structure and/or context feature the capability to fly, a collection of cards, a measured height of 170cm. has item is a relation between a collection and an item contained therein. has item has feature is a relation between a thing and an internal, contextual, or externally attributed characteristic. has feature A collection is an information object for which there may be zero or more items. collection a stamp collection, a murder of crows, the arm of a clinical trial is feature of is a relation between an internal, contextual, or externally attributed characteristic and some Thing. is feature of A quality is a feature that is intrinsically associated with its bearer (or its parts). the color of an apple, the smoothness of skin, the brightness of a star, the speed of an event quality is direct part is a non-transitive parthood relation that can be used to specify cardinality constraints between a part and its whole. is direct part of has direct part is a non-transitive parthood relation that can be used to specify cardinality constraints between a whole and its parts. has direct part time is a quantity pertaining to the duration of some interval of time or a particular instant of time (against some frame of reference). time An object is an entity that maintains its identity through time, and does not have processes as its parts. object a heart, the function to pump blood, the role of a doctor is part of is a transitive, reflexive and antisymmetric relation between a part and itself or a part and a whole. is part of time instant is a quantity of time a particular moment in time. time instant is participant in is a relation to relate an object and the process in which it participates. is participant in an information object is a feature that represents, is about, or encodes some information. information object A role is a feature that describes a context-dependent behaviour. role a teacher, a student, a catalyst, a substrate, a product, a patient has part is a transitive, reflexive and antisymmetric relation between a whole and itself or a whole and its part. has part A time interval is a quantity for a continuous and bounded extent of time, characterized by a start time and an end time. time interval 0.0 A spatial object is an object that occupies space spatial object a mountain, a planet, a photon, the lining of the stomach, the cavity of the stomach, the space between mars and earth has participant is a relation that describes the participation of a (non-process) thing in a process. has participant a start time is a time instant at the beginning of a process/time interval. start time a relation between a time and an object that occurs within it. is time of a process is a entity that unfolds in time, has temporal parts, and has objects that participate in the process. process the process of diagnosing a problem condition, the process of walking down the street, the process of teaching a class A capability is a feature that describes what an entity is able to do, under some set of circumstances. capability the capability to fly, the capabilty to reduce the activation energy of a chemical reaction, the capability to reason