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
Formally étale morphism topology, the notion of formally étale for schemes is analogous to formally étale for the discrete topology for rings. That is, a morphism of schemes is formally étale if for every affine "Y"-scheme "Z", every nilpotent sheaf of ideals "J" on "Z" with be the closed immersion determined by "J", and every "Y"-morphism , there exists a unique "Y"-morphism such that . It is equivalent to let "Z" be any "Y"-scheme and let "J" be a locally nilpotent sheaf of ideals on "Z". Formally étale morphism In commutative algebra and algebraic geometry, a morphism is called formally étale if it