A line through a column in MathML
From https://groups.google.com/d/msg/mathjax-users/qWvLzkrrWuo/F78PeixM-AgJ
How can I draw a line through a column (row and column at the same time) in a matrix?
An example in TEX: Draw a line through one column of a matrix
There isn't really a direct way to do this in MathML (or in TeX for
that matter, tikz is getting help from the back end system and taking
two runs of the document in the linked example) probably the simplest
thing would be to put each entry in the column in an menclosed with
notation="verticalstrike" so that each entry is struck out. You could
do that same in a row and use notation="verticalstrike horizontalstrike" at the crossing point.
David
(That's from a mathml spec standpoint, I haven't checked that the implementations support all the attributes needed)