Geometry of generic Moishezon twistor spaces on 4CP^2, II: degenerate cases
arXiv:1109.5427
Abstract
We continue to study twistor spaces on the connected sum of four complex projective planes, whose anticanonical map is of degree two over the image. In particular, we determine the defining equation of the branch divisor of the anticanonical map in an explicit form. Together with previous two articles (arXiv:1009.3153 and arXiv:0705.0060), this completes explicit description of all such twistor spaces.
arXiv comment22 pages, 3 figures. I will not submit this article to any journal, because half of the results are included in another paper "Double solid twistor spaces II: general case"