title: Shafarevich theorem
text: # Shafarevich theorem
  
  In mathematics, the Shafarevich theorem, named for Igor Shafarevich, may refer to:
  
  * Néron–Ogg–Shafarevich criterion
  * Golod–Shafarevich theorem about class field towers
  * Grothendieck–Ogg–Shafarevich formula
  * Shafarevich's theorem on solvable Galois groups
  * Shafarevich–Weil theorem about the fundamental class in class field theory
  * Shafarevich's theorem on elliptic curves with good reduction outside a given set.
  