Present Continuous Tense (Negative form)

I am writing = من دارم مي نويسم /man da:ram minevisam/
I am not writing = من دارم نمي نويسم /man da:ram neminevisam/

Note: the structure is correct. However, we'd better use the negative form in S.P.T for it in P.C.T. So :

I am not writing = من نمي نويسم /man neminevisam/

see 73