Why is a set of functions v(t) dense in L^2

[4real4sure]

Hello,

I was going through the following paper: http://www.emis.de/journals/HOA/AAA/Volume2011/142128.pdf

In page 6, immediately after equation (3.15), its written that "functions of the form v(t) are dense in L^2". I have been looking for proofs online which verifies the above statement but unable to find one. I would appreciate if someone can direct me to a link or explain with proof of how the functions of the form v(t) are dense in L^2.

Thank you,

 

[Stephen Tashi]

Since you haven't received any replies yet, I suggest that you at least sketch a definition of the functions v(t) in a post. An expert in the topic might breeze through the paper in your link, but you may need to appeal to non-experts in the topic to get an answer.

 

[WWGD]

But it seems like natural courtesy that if you want others' help that you should be the one to lay out the
definitions for those whose help you seek.