Using the latex_name parameter of `var`

just changes the way the variable `v`

is printed. You want to change the way specific vector objects are printed, if I understand correctly. Calling `latex()`

on `v`

calls the `_latex_()`

method of `v`

, followed by converting to a `LatexExpr`

object.

```
sage: v = vector([1,2,3])
sage: v._latex_()
'\\left(1,\\,2,\\,3\\right)'
```

So you could define your own `latex`

method for vectors that does the same thing, but puts `\mid`

between entries instead of commas. Below, I copied the code from `v._latex_()`

that I looked at using `v._latex_??`

in the Sage console and then modified the last line (adding `LatexExpr`

) and the second to last line (replacing the comma with `\mid`

).

```
def my_vector_latex(v):
latex = sage.misc.latex.latex
LatexExpr = sage.misc.latex.LatexExpr
vector_delimiters = latex.vector_delimiters()
s = '\\left' + vector_delimiters[0]
s += '\\mid\\,'.join([latex(a) for a in v.list()]) # different than usual _latex_()
return LatexExpr(s + '\\right' + vector_delimiters[1])
```

Then, you can do:

```
sage: latex(v)
\left(1,\,2,\,3\right)
sage: my_vector_latex(v)
\left(1\mid\,2\mid\,3\right)
```