+ Commands: xrightarrow, xleftarrow, substack, underset, dddot
+ over/under arrows (e.g. underleftarrow).
+ Environments: align, alignat, xalignat, xxalignat, multline, gather
+ split, gathered, aligned, cases, subarray, pmatrix, bmatrix, vmatrix,
+ Vmatrix
+
+- Preliminary support for xymatrix
+
+- Support for horizontal and vertical lines in arrays.