Article Q: elected as/appointed as + no article + position

[vcolts]

Ex1:

a. Obama was elected as president in 2008.
b. Obama was elected as the president in 2008.
c. Obama was elected as a president in 2008.

Ex2: J

a. Jackson was appointed as chairman in 2010.
b. Jackson was appointed as the chariman in 2010.
c. Jackson was appointed as a chairman in 2010.

My understanding is that (A) is the most used form while (B) and (C) are also grammatically correct.

My question: In the case of (A), why is the article "the" or even "a" missing? Why is it grammatically acceptable to put no article there?


Thanks in advance.

[abaka]

The most common version is:

Obama was elected president in 2008. Jackson was appointed chairman in 2010.

The three you have are all used, but frankly sound a little odd unless in context.

I think the best explanation is that in conversation rhythm must be maintained, and so there exists a limited amount of flexibility beyond the strict grammatical prescriptions.