title: Quartic threefold
text: # Quartic threefold
  
  In algebraic geometry, a quartic threefold is a degree 4 hypersurface of dimension 3 in 4-dimensional projective space. Iskovskih & Manin (1971) showed that all non-singular quartic threefolds are irrational, though some of them are unirational.
  
  ## Examples
  
  * Burkhardt quartic
  * Igusa quartic
  