Because Bobby Valentine is in the last year of his contract with the Mets, his future status with them has been a frequent topic of conversation this season.
The tragedy in Afghanistan has been a frequent topic, too, and one that all of the candidates feel an obligation to acknowledge.
Friends and industry insiders have been aware for more than a decade, and rumors that he may be gay have been a frequent topic of discussion in skateboard corners of the internet.
Since The Globe's article, the Ellis case has been a frequent topic of newspaper editorials and water-cooler conversation, causing many in the universities to re-examine their ethical codes and disciplinary procedures.
Given this backdrop and these fears, "tail risk" hedging, or protecting investment portfolios against extreme negative moves in the market, has been a frequent topic of conversation among market participants.
The concept of deep learning or deep structured learning has been a frequent topic of conversation in recent months because of the commitment and advancements of some of the world's largest and most prolific search companies.
