Topic Map engineering includes several activities, one of them being authoring of maps. The authoring language AsTMa= itself is designed for human authoring, not so much for exchange of Topic Map documents between computers, as is XTM. This implies that the language is rather non-orthogonal by design and follows much more a do-what-I-mean (DWIM) instead of a do-what-I-say approach. It also implies that TM constructs which arguably are used more frequently than others can be written in more concise ways than unpopular ones. Additionally, the language adopts several different ways to express one and the same thing.