Normal bundles of rational curves inP 3

1980 ◽  
Vol 33 (2) ◽  
pp. 111-128 ◽  
Author(s):  
Franco Ghione ◽  
Gianni Sacchiero
2019 ◽  
Vol 21 (02) ◽  
pp. 1850011 ◽  
Author(s):  
Izzet Coskun ◽  
Eric Riedl

Let [Formula: see text] be a general Fano complete intersection of type [Formula: see text]. If at least one [Formula: see text] is greater than [Formula: see text], we show that [Formula: see text] contains rational curves of degree [Formula: see text] with balanced normal bundle. If all [Formula: see text] are [Formula: see text] and [Formula: see text], we show that [Formula: see text] contains rational curves of degree [Formula: see text] with balanced normal bundle. As an application, we prove a stronger version of the theorem of Tian [27], Chen and Zhu [4] that [Formula: see text] is separably rationally connected by exhibiting very free rational curves in [Formula: see text] of optimal degrees.


2017 ◽  
Vol 63 (2) ◽  
pp. 211-220 ◽  
Author(s):  
Alberto Alzati ◽  
Riccardo Re

2012 ◽  
Vol 16 (2) ◽  
pp. 237-270 ◽  
Author(s):  
Mingmin Shen

2006 ◽  
Vol 76 (1) ◽  
pp. 57-63
Author(s):  
U. Bruzzo ◽  
A. Ricco

2017 ◽  
Vol 288 (3-4) ◽  
pp. 803-827 ◽  
Author(s):  
Izzet Coskun ◽  
Eric Riedl

2018 ◽  
Vol 18 (4) ◽  
pp. 451-465
Author(s):  
Adrian Zahariuc

Abstract We exploit an elementary specialization technique to study rational curves on Fano varieties of index one less than their dimension, known as del Pezzo manifolds. First, we study the splitting type of the normal bundles of the rational curves. Second, we prove a simple formula relating the number of rational curves passing through a suitable number of points in the case of threefolds and the analogous invariants for del Pezzo surfaces.


2021 ◽  
Vol 8 (1) ◽  
pp. 208-222
Author(s):  
Georges Dloussky

Abstract Let S be a compact complex surface in class VII0 + containing a cycle of rational curves C = ∑Dj . Let D = C + A be the maximal connected divisor containing C. If there is another connected component of curves C ′ then C ′ is a cycle of rational curves, A = 0 and S is a Inoue-Hirzebruch surface. If there is only one connected component D then each connected component Ai of A is a chain of rational curves which intersects a curve Dj of the cycle and for each curve Dj of the cycle there at most one chain which meets Dj . In other words, we do not prove the existence of curves other those of the cycle C, but if some other curves exist the maximal divisor looks like the maximal divisor of a Kato surface with perhaps missing curves. The proof of this topological result is an application of Donaldson theorem on trivialization of the intersection form and of deformation theory. We apply this result to show that a twisted logarithmic 1-form has a trivial vanishing divisor.


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