No.

It is useful to have names for matrices. Usually a bold lower case letter is used for a column or a row matrix:

a= ( 1.2, -3.6 )x= ( x_{1}, x_{2}, x_{3}, x_{4})r= ( r_{0}, r_{1})^{T}

It is conventional to use names from the start of the alphabet for column
matrices whose elements we know (like **a** above),
and to use names from the end of the alphabet for column matrices whose elements
are variables.

Often the names of column matrix elements are subscripted versions of the
name of the whole column matrix (like column matrix **r**
and its elements r_{0} and r_{1}).

Bold face is hard to do with pencil or chalk, so instead an arrow or a bar is placed over the name:

__{->}x x

Say that you know:

x= ( x_{1}, x_{2})y= ( 3.2, -8.6 )x=y

What must be true about **x _{1}** and