12. The method of claim 8 , wherein the information associated with the grouped input strokes includes shape and time series information.
8. A method performed by a computing device having a processor and a memory for grouping and recognizing symbols of a handwritten mathematical expression, the method comprising: receiving a plurality of input strokes corresponding to a handwritten mathematical expression; grouping the plurality of input strokes into symbols based upon intra-group and inter-group information associated with the input strokes; and recognizing the symbols based upon information associated with the grouped input strokes wherein the intra-group information associated with the input strokes includes a confidence representative of whether the input strokes are a certain symbol provided by the recognizing, and a score representative of whether the input strokes are a valid symbol based upon intra-group spatial information that includes a size difference among the input strokes and an offset measurement among the input strokes; wherein the grouping receives the input strokes, determines intra-group spatial information among the input strokes, and determines whether to group the input strokes into a symbol based upon the intra-group spatial information; and wherein computer-executable instructions implementing the method are stored in the memory of the computing device for execution by the processor of the computing device.