Semantic Enrichment of Mathematics via ‘tooltips’

Abstract

A package mathsem for pdf-

implements a way to provide semantic meaning to symbols, without adding a large syntactical burden to the specification of a mathematical expression. It uses a concept of ‘active comment’, allowing the ‘%’ character at the beginning of a new line to become an active token under highly-controlled circumstances. With a strictly defined syntax, words to express the semantic meaning of a variable (‘x’ say) can be associated with each occurrence of ‘x’ in the expression following. The words become content of a tooltip, that ‘pops-up’ by the symbol in a PDF document. The idea extends to:

• 1. allow multiple instances of the same symbol have distinct meanings;

• 2. attach semantics to macro-names as well as character symbols;

• 3. allow nested tooltip rectangles, for sub-expressions;

• 4. assign defaults to be attached to symbols and macros, at either global or local levels, to maintain consistency of meaning within extended portions of a document.

It is planned to use the same syntactical constructions to provide words for spoken ‘alternative text’, in the context of fully-tagged, accessible, mathematical content within PDF documents

Thanks to Michael Kohlhase for ideas suggesting such a package.