Assess whether the following scenarios contain defamatory actions, and advise whether there are any available defences.

Yifan and Giannis are employees at the Caribbean University ("CU"). Yifan is a Lecturer and Giannis is a Professor. Yifan applies for the post of Senior Lecturer and Petra, who is the Chairman of the Board of Academic Affairs at CU asks Giannis to provide an assessment of Yifan's suitability for post.

Giannis consults with his colleague Marc who recently co-authored a book with Yifan. However, unbeknownst to Giannis the relationship between Yifan and Marc is strained, as Marc suspects his wife is in a relationship with Yifan. Marc tells Giannis that Yifan stole his research and failed to properly credit him in a recent academic article.

Giannis submits a memorandum to Petra which contains the following statement:

"Yifan has worked at CU for 5 years, notwithstanding his strong publication record, I am unable to support Yifan's promotion because I have heard that he has plagiarized a fellow colleague's work. I consider such an act to be most disreputable and as such it is my assessment of Yifan is that he lacks integrity, and he is not a suitable candidate."

There is no evidence that Yifan plagarised any work.

Petra circulates Yifan's memorandum to the Selection Committee responsible for hiring. Yifan's application is unsuccessful.

Answer using the IRAC method.