dual X
i1 : X = PP_QQ^(2,2); o1 : ProjectiveVariety, surface in PP^5
i2 : X' = dual X; o2 : ProjectiveVariety, hypersurface in PP^5
i3 : describe X' o3 = ambient:.............. PP^5 dim:.................. 4 codim:................ 1 degree:............... 3 generators:........... 3^1 purity:............... true dim sing. l.:......... 2 gens sing. l.:........ 2^6
i4 : assert(dual X' == X)