scholarly journals On regular surfaces of general type with pg = 2 and non-birational bicanonical map

2002 ◽  
pp. 65-78
2001 ◽  
Vol 33 (3) ◽  
pp. 265-274 ◽  
Author(s):  
MARGARIDA MENDES LOPES ◽  
RITA PARDINI

A minimal surface of general type with pg(S) = 0 satisfies 1 [les ] K2 [les ] 9, and it is known that the image of the bicanonical map φ is a surface for K2S [ges ] 2, whilst for K2S [ges ] 5, the bicanonical map is always a morphism. In this paper it is shown that φ is birational if K2S = 9, and that the degree of φ is at most 2 if K2S = 7 or K2S = 8.By presenting two examples of surfaces S with K2S = 7 and 8 and bicanonical map of degree 2, it is also shown that this result is sharp. The example with K2S = 8 is, to our knowledge, a new example of a surface of general type with pg = 0.The degree of φ is also calculated for two other known surfaces of general type with pg = 0 and K2S = 8. In both cases, the bicanonical map turns out to be birational.


1997 ◽  
Vol 224 (1) ◽  
pp. 137-166 ◽  
Author(s):  
Ciro Ciliberto ◽  
Paolo Francia ◽  
Margarida Mendes Lopes

2015 ◽  
Vol 26 (05) ◽  
pp. 1550035 ◽  
Author(s):  
Carlos Rito

We give a list of possibilities for surfaces of general type with pg = 0 having an involution i such that the bicanonical map of S is not composed with i and S/i is not rational. Some examples with K2 = 4, …, 7 are constructed as double coverings of an Enriques surface. These surfaces have a description as bidouble coverings of the plane.


2010 ◽  
Vol 53 (4) ◽  
pp. 746-756
Author(s):  
Caryn Werner

AbstractWe construct new examples of surfaces of general type with pg = 0 and K2 = 5 as ℤ2 × ℤ2-covers and show that they are genus three hyperelliptic fibrations with bicanonical map of degree two.


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