Abstract
CAT4 is proposed as a general method for representing information, enabling a powerful programming
method for large-scale information systems. It enables generalised machine learning, software
automation and novel AI capabilities. It is based on a special type of relation called CAT4, which is
interpreted to provide a semantic representation. This is Part 1 of a five-part introduction. The focus
here is on defining the key mathematical structures first, and presenting the semantic-database
application in subsequent Parts. We focus in Part 1 on general axioms for the structures, and introduce
key concepts. Part 2 analyses the CAT2 sub-relation of CAT4 in more detail. The interpretation of fact
networks is introduced in Part 3, where we turn to interpreting semantics. We start with examples of
relational and graph databases, with methods to translate them into CAT3 networks, with the aim of
retaining the meaning of information. The full application to semantic theory comes in Part 4, where
we introduce general functions, including the language interpretation or linguistic functions. The
representation of linear symbolic languages, including natural languages and formal symbolic
languages, is a function that CAT4 is uniquely suited to. In Part 5, we turn to software design
considerations, to show how files, indexes, functions and screens can be defined to implement a CAT4
system efficiently