But there's a certain niggling rivalry in there too.
The second was that certain rivalries had to be kept intact.
There is thought to be a certain degree of rivalry between the two men, and Mr. Zarqawi may have been trying to remind the world how active he has been in recent years compared with Mr. bin Laden.
The teams share information, but there is a certain amount of cheerful rivalry among them.
There must have been a certain amount of sibling rivalry in the Sidney establishment.
Cast three major stars in Chekhov's "Three Sisters" and you might expect a certain measure of sibling rivalry.
"Towards the end, a certain degree of sibling rivalry pushed them both to complete their theses roughly at the same time," Jennings says.
Understanding the Vicenza-Verona rivalry requires a certain grasp of Italian history and there is an old Veneto saying: Veneziani gran signori, Padovani gran dottori, Vicentini magnagati, Veronesi tutti mati.
One sportswriter famously described a certain New York-Boston sports rivalry as akin to the hammer and the nail, but increasingly the teams up north are racking up trophies, and there's no better place — outside of Massachusetts, of course — to take in the action.
These findings suggest that binocular rivalry has a certain insensitivity to recurrent temporal modulations.
