How can I desplay subscripts.

I do not have a special way of displaying the subscripts. I write p1,typing first the p and after 1. My question is how to display the subscripts. Is 1 in p1 a subscript? I think no.

[Walter Roberson]

Smaller letters is a matter of display, not a matter of computation. In order for us to tell you how to achieve the display you desire, you need to specify how you are doing the displaying.

We are still waiting for you to answer this over in http://uk.mathworks.com/matlabcentral/answers/231183-how-can-i-put-subscripts-on-a-polynomial-of-degree-n

[Andreas Sorgatz]

Execute

    syms p1 pn p_n;
    p1+p_n+pn

in MATLAB Live Editor in R2016a or later. There the output should meet your expectation.