Quartic surface

In mathematics, especially in algebraic geometry, a quartic surface is a surface defined by an equation of degree 4.

More specifically there are two closely related types of quartic surface: affine and projective. An affine quartic surface is the solution set of an equation of the form

f(x,y,z)=0 

where f is a polynomial of degree 4, such as ⁠f(x,y,z)=x4+y4+xyz+z2−1⁠. This is a surface in affine space A3.

On the other hand, a projective quartic surface is a surface in projective space P3 of the same form, but now f is a homogeneous polynomial of 4 variables of degree 4, so for example ⁠f(x,y,z,w)=x4+y4+xyzw+z2w2−w4⁠.

If the base field is ⁠ℝ⁠ or ⁠ℂ⁠ the surface is said to be real or complex respectively. One must be careful to distinguish between algebraic Riemann surfaces, which are in fact quartic curves over ⁠ℂ⁠, and quartic surfaces over ⁠ℝ⁠. For instance, the Klein quartic is a real surface given as a quartic curve over ⁠ℂ⁠. If on the other hand the base field is finite, then it is said to be an arithmetic quartic surface.

Special quartic surfaces

See also

References