The JIITs (Just-In-Time-Trees) paradigm is based on the idea that markup trees should be asserted and recognized during processing and not determined as part of markup. Asserting trees allows multiple trees to be represented by markup without conflict in a document.

The JITTs proposal takes advantage of the latest revisions to the XSLT standard and freely available software to implement the markup recognition required by this method. Using XSLT, valid or well-formed trees can be produced from SGML and XML files that contain what would otherwise be considered invalid markup.

Markup recognition and XSLT allows the production of a variety of well-formed and or valid document instances from a variety of extant formats, such as non-well-formed XML files, MECS, traditional SGML files using concur, and LMNL. One purpose of this demonstration is to assure the XML community that implementation of JITTs will not require the rewriting of any extant software or texts in order to obtain the advantages offered by this new technique.

Beyond producing valid or well-formed XML files, JITTs will also be used to contrast its answer to the question "Are Simple Trees Enough?" with that of standard XML markup when addressing the need to reproduce complex text structures. That answer will be illustrated by encoding several mansucript pages of Charles Pierce on existential graphs, a fairly complex text from an information standpoint, by use of JITTs and a layered output format (SVG) to illustrate one possible way of encoding this material. Existential graphs underlie current research on conceptual graphs and other topics related to modern research on information technology. A robust means of making the primary source materials on existential graphs available to the researh community will further both that research and the development of richer markup systems for such materials.