Subject with commas:

[Piak]

Dear Sirs,

This is another confusing case. What do you think about this question?
*With this statement, there is a sentence (that clause) contains many names as its subject without using “and” but they are separated by commas, what should it be in the predicative (I mean should it be “are or is”), please? The District Registration Office has inquired the petitioner and documentary evidence, it is assured that Miss. Pradtha, Miss. Ketkan, Miss. Kanok, Miss. Chonya, according to the above said evidence, is the same (identical) person. *

Thank you and best regards,
Piak

[Casiopea]

They are the same person.

Miss Pradtha, Miss Ketkan, Miss Kanok, Miss Chonya are one and the same person.

Others
Miss Pradtha goes by three other names: Miss Ketkan, Miss Kanok, Miss Chonya.
Miss Pradtha, a.k.a. Miss Ketkan, Miss Kanok, Miss Chonya, .... (also known as)

Note that, the title Miss does not require a period *Miss.

[Piak]

Dear Casiopea,

Thank for your reply, but I don't understand why we don't need a period after Miss. Could you give more details, please? Because I normally use and see it that way.

And what does a.k.a means?

Thank you.
Best regards,
Piak

[Casiopea]

I don't understand why we don't need a period after Miss. Could you give more details, please? And what does a.k.a means?

You're welcome.

Miss is an abbreviation of Mistress: Mistress => Miss

Miss ends in -ss, which are the last two letters in the word Mistress, so no period is required.

Ms. is abbreviated from Mrs.: Mrs. => delete -r => Ms.)

a.k.a. means, also known as.

[Piak]

Dear Casiopea,

Those are my new knowledge of the English language that I have just known. Thank you very much for such the new things that I would have known it before.

Best regards,
Piak

[Casiopea]

You're welcome.