Hemicrania continua for the headache. When the symptoms of hemicrania continua are present, it's considered "diagnostic" if they respond completely to indomethacin. The efficacy of indomethacin may not be long term for all patients, as can eventually become ineffective. The factor that allows hemicrania continua and its exacerbations to be differentiated from migraine and cluster headache is that hemicrania continua is completely responsive to indomethacin. Triptans and other abortive medications do not affect hemicrania continua. In addition to persistent daily headache of HC, which is usually mild to moderate (and frequently severe), HC can present other symptoms. These additional symptoms of HC
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