Thank you very much for your answer!

@Wojowu it is a Banach algebra structure but what about injective Banach algebra morphisms?You possibly means that it is non rigid as a Banach algebra too?

@BillJohnson Dear Prof. Johnson thank you very much for your comment and your attention to this post.

Thank you very much Lorenzo for your answer

Thank you very much for your answer

Thank you very much for your answer

@SArgyros I have no idea. is n fix in your question? Do you mean that such a possible $\epsilon$ and $\delta$ work for all $n\in \mathbb{N}$? Could you plz elaborate the last part of your comment? (In particular the measur language you used in the last part). Is $\mu_{x_n}$ the dirac measure ? Or some thing else?

@მამუკაჯიბლაძე I can not find your home page and your email address. I would appreciate if you send me an email to my yahoo email "[email protected]". Thank you

@fedja I do not have your email address. I would appreciate if you send me email for more discussion. My email adreess is written in my profile.

@SArgyros I do not have your email address. I would appreciate if you send me email for more discussion. My email adreess is written in my profile.