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 smooth map Formally smooth map In algebraic geometry and commutative algebra, a ring homomorphism formula_1 is called formally smooth (from French: "Formellement lisse") if it satisfies the following infinitesimal lifting property: Suppose "B" is given the structure of an "A"-algebra via the map "f". Given a commutative "A"-algebra, "C", and a nilpotent ideal formula_2, any "A"-algebra homomorphism formula_3 may be lifted to an "A"-algebra map formula_4. If moreover any such lifting is unique, then "f" is said to be formally étale. Formally smooth maps were defined by Alexander Grothendieck in "Éléments de géométrie algébrique" IV. For finitely presented morphisms, formal smoothness is