Chronic paroxysmal hemicrania Chronic paroxysmal hemicrania Chronic paroxysmal hemicrania (CPH), also known as Sjaastad syndrome, is a severe debilitating unilateral headache usually affecting the area around the eye. It normally consists of multiple severe, yet short, headache attacks affecting only one side of the cranium. It is more commonly diagnosed in women than in men, but, unlike a migraine, has no neurological symptoms associated with it. CPH headaches are treated through the use of non-steroidal anti-inflammatory drugs, with indomethacin found to be usually effective in eliminating symptoms. Paroxysmal hemicrania is classified by the frequency and duration of attacks experienced by patients. Episodic paroxysmal
Formally real field properties are equivalent. It is also easy to see that a field that admits an ordering must satisfy these three properties. A proof that if "F" satisfies these three properties, then "F" admits an ordering uses the notion of and positive cones. Suppose −1 is not a sum of squares, then a Zorn's Lemma argument shows that the prepositive cone of sums of squares can be extended to a positive cone . One uses this positive cone to define an ordering: if and only if belongs to "P". A formally real field with no formally real proper algebraic extension is