ICHD classification and diagnosis of migraine are further subdivided. Overall ICHD-3 beta distinguishes 29 migraine subtypes. The following table outlines the main subtypes and their ICHD-1, -2, -3 beta and ICD-10 codes. Migraine without aura also referred to as a "common migraine", (previously known as "hemicrania simplex") is a specific neurological disorder characterized by recurrent, throbbing headaches that often affect one side of the head (i.e., it is unilateral), are of at least moderate intensity, and may cause nausea, phonophobia or photophobia. One defining characteristic of the common migraine is a lack of the visual disturbances known as an aura. The exact International Classification of Headache
Relatively hyperbolic group a relatively hyperbolic group, as formulated by Bowditch goes as follows. A group "G" is said to be hyperbolic relative to a subgroup "H" if the coned off Cayley graph formula_2 has the properties: If only the first condition holds then the group "G" is said to be weakly relatively hyperbolic with respect to "H". The definition of the coned off Cayley graph can be generalized to the case of a collection of subgroups and yields the corresponding notion of relative hyperbolicity. A group "G" which contains no collection of subgroups with respect to which it is relatively hyperbolic is