Is this a sentence fragment?
A new detective series by J. K. Rowling published under the pseudonym of Robert Galbraith after she completed her seven-volume Harry Potter series.
A: yes
B: no
This is a sentence fragment. It does not express a complete thought.
A new detective series by J. K. Rowling published under the pseudonym of Robert Galbraith after she completed her seven-volume Harry Potter series.
Here is one way to fix the sentence fragment:
Author J. K. Rowling released a new detective series published under the pseudonym of Robert Galbraith after she completed her seven-volume Harry Potter series.