One-third hypothesis the cohesiveness of the group that is one-third. According to the binomial coefficient a group of size r occurs in a population of size n in formula_1 ways. Because each group of size r can dissolve in "2" subgroups, the total number of ways all groups of size r can emerge and dissolve equals "3", in keeping with the summation: formula_2 Said otherwise, large groups close to two-thirds of the population will be more likely than any other groups to dissolve into splinter groups. A corollary of this consideration is that much smaller groups will be the ones most likely
Four Thirds system Thirds cameras came to an end after the introduction of the mirrorless Micro Four Thirds format. Discontinued models include: The Four Thirds lens mount is specified to be a bayonet type with a flange focal distance of 38.67 mm. There are currently around three dozen lenses for the Four Thirds System standard. Before announcing that it would stop production of Four Thirds lenses in early 2017, Olympus produced about 20 lenses for the Four Thirds System under their "Zuiko Digital" brand. They are divided into three grades — Standard, High Grade and Super High Grade. High Grade lenses have faster