This paper presents a framework for representing and querying spatio-temporal data, focusing on moving objects. The authors propose a system of abstract data types to model time-dependent geometries, including those that change continuously. The framework includes basic types such as integers, booleans, points, lines, regions, and time. Type constructors are used to create new types, such as moving point and moving region, which represent objects whose positions or extents change over time. The framework emphasizes closure, simplicity, and expressiveness, ensuring that operations are consistent across different types. The design allows for the representation of moving objects as functions from time to spatial types, enabling the modeling of continuous movement. The paper defines operations for spatial and temporal types, ensuring that they behave consistently across different dimensions and spaces. It also discusses the importance of closure between non-temporal and temporal types, and provides examples of how these types can be used in queries. The framework is designed to be integrated into query languages, enabling powerful spatio-temporal queries. The paper also addresses the need for aggregate functions and operations that handle sets of intervals, ensuring that the system can handle a wide range of spatio-temporal data. The design is based on principles of consistency, closure, and expressiveness, and provides a foundation for implementing spatio-temporal databases.This paper presents a framework for representing and querying spatio-temporal data, focusing on moving objects. The authors propose a system of abstract data types to model time-dependent geometries, including those that change continuously. The framework includes basic types such as integers, booleans, points, lines, regions, and time. Type constructors are used to create new types, such as moving point and moving region, which represent objects whose positions or extents change over time. The framework emphasizes closure, simplicity, and expressiveness, ensuring that operations are consistent across different types. The design allows for the representation of moving objects as functions from time to spatial types, enabling the modeling of continuous movement. The paper defines operations for spatial and temporal types, ensuring that they behave consistently across different dimensions and spaces. It also discusses the importance of closure between non-temporal and temporal types, and provides examples of how these types can be used in queries. The framework is designed to be integrated into query languages, enabling powerful spatio-temporal queries. The paper also addresses the need for aggregate functions and operations that handle sets of intervals, ensuring that the system can handle a wide range of spatio-temporal data. The design is based on principles of consistency, closure, and expressiveness, and provides a foundation for implementing spatio-temporal databases.