In standard form of LP we have $n$ variable and $m$ constraint. In simplex algorithm we set all non-basic variable to zero and at most $m$ basic variable have positive value.
if $m < n$, then at least $n-m$ variables would be zero. Is it a valid LP problem? Can solve a LP that $m < n$?
Minimize $f(x_1,x_2)=x_2$ where $x_1, x_2\geq 0$.
[In the sense of linear programming this would count as a problem with zero constrains. In standard form the non-negativity of the variables is always there, so one would rather count the constrains that are equations.]