18. The system of claim 15 , wherein the application program further includes a parser configured to parse each of the plurality of candidates and adjust a rank of the candidates based at least whether a syntax error is encountered during parsing.
15. A system for use in handwriting recognition in computer algebra, comprising: an application program and a recognizer each executable on a computing device, the application program being configured to display a graphical user interface on a display associated with the computing device, and being configured to receive handwriting input from a handwriting input device associated with the computing device, via the recognizer, the handwriting input representing a mathematical expression; wherein the recognizer is configured to process the handwriting input to recognize a plurality of candidates, rank the plurality of candidates in initial candidate data, and return the initial candidate data to the application program via an application programming interface; wherein the application program is configured to scan the plurality of candidates for segments that match application-level criteria, and adjust a rank of one or more of the plurality of candidates that match the application-level criteria, to form a processed candidate list, and display the processed candidate list including the plurality of candidates with rank adjusted based on application-level criteria, via the graphical user interface.