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This paper provides an axiomatic formalization of a theory of foundational relations between three categories of entities: individuals, universals, and collections. We deal with a variety of relations between entities in these categories, including the is-a relation among universals and the part-of relation among individuals as well as cross-category(More)
OBJECTIVE The objective of this paper is to demonstrate how a formal spatial theory can be used as an important tool for disambiguating the spatial information embodied in biomedical ontologies and for enhancing their automatic reasoning capabilities. METHOD AND MATERIALS This paper presents a formal theory of parthood and location relations among(More)
Parthood, componenthood, and containment relations are commonly assumed in biomedical ontolo-gies and terminology systems, but are not usually clearly distinguished from another. This paper contributes towards a unified theory of parthood, com-ponenthood, and containment relations. Our goal in this is to clarify distinctions between these relations as well(More)
We develop a formal theory of mereology that includes relations that change over time. We show how this theory formalizes reasoning over domains of material objects, which include not only integral objects (my computer, your liver) but also portions of stuff (the water in your glass, the blood in a vial). In particular, we use different mereological(More)
In fields such as medicine, geography, and mechanics, spatial reasoning involves reasoning about entities that may coincide without overlapping. Some examples are: cavities and invading particles, passageways and valves, geographic regions and tropical storms. The purpose of this paper is to develop a formal theory of spatial relations for domains that(More)
We present a formal theory of qualitative distances between regions based on qualitative size relations. Using standard mereological relations, a sphere-predicate, and qualitative size relations such as roughly-the-samesize-as and negligible-in-size-with-respect-to, we define qualitative distance relations such as close-to, near-to, away-from, and(More)
OBJECTIVE To determine the prevalence of JC virus (JCV) reactivation and JCV-specific cellular immune response during prolonged natalizumab treatment for multiple sclerosis (MS). METHODS We enrolled 43 JCV-seropositive MS patients, including 32 on natalizumab monotherapy >18 months, 6 on interferon β-1a monotherapy >36 months, and 5 untreated controls. We(More)