John Christian Ottem
University of Oslo
Box 1053, Blindern
My research interests are in algebraic geometry, in particular
birational geometry, Calabi-Yau manifolds, and Hodge theory.
geometry group at UiO
geometry seminar at UiO.
Moduli and Algebraic Cycles Research programme at the Mittag-Leffler Institute, Fall 2021.
Enumeration and Moduli: A conference in algebraic geometry on the
occasion of Geir Ellingsrud's 70th birthday. December 6-8 2018, University of Oslo.
Combinatorics and Hodge theory. 18-22 June 2018, Sophus Lie Conference Center, Nordfjordeid, Norway.
Geometry of Moduli.
August 7, 2017 - Aug. 11, 2017, Lofoten, Norway.
Polar geometry: A conference celebrating the work of Ragni Piene on the occasion of her 70th birthday.
January 26-28, 2017, University of Oslo.
Nordfjordeid Summer School: Stability conditions on triangulated categories and geometric applications.
June 13-17, 2016, Sophus Lie Conference Center, Nordfjordeid, Norway.
Tropical degenerations and stable rationality
(with J. Nicaise) (2019)
A pencil of Enriques surfaces with non-algebraic integral Hodge classes
(with F. Suzuki) (2019)
On deformations of quintic and septic hypersurfaces
(with S. Schreieder) (2018)
Journal de Mathématiques Pures et
Appliquées (to appear)
on the positivity of the cotangent bundle of a K3 surface
(with F. Gounelas) (2018)
Curve classes on irreducible holomorphic symplectic varieties (with
Communications in Contemporary Mathematics
Failure of the integral Hodge conjecture for threefolds of Kodaira
dimension zero (with O. Benoist).
Helvetici (to appear)
A counterexample to the birational Torelli problem for
Calabi-Yau 3-folds (with J. V. Rennemo).
Journal of the London Mathematical Society 97 (2018), 427-440
Positivity of the diagonal (with
Advances in Mathematics 335 (2018), 664-695.
Effective cones of cycles on blow-ups of projective space (with
I. Coskun, J. Lesieutre).
Algebra & Number Theory 10-9 (2016).
on some hyperkahler fourfolds.
LMS volume for Fulton 80 (to appear)
disjoint from a nef divisor (with J. Lesieutre).
Mathematical Journal 65 (2016), 321-332.
subvarieties with ample normal bundle.
Journal of the European Mathematical Society 18 (2016), 2459-2468
Birational geometry of hypersurfaces in products of projective
Mathematische Zeitschrift 280 (2015), 135-148
Quartic spectrahedra (with K. Ranestad, B. Sturmfels,
Math. Prog. B (2015).
Ample subvarieties and q-ample divisors.
Advances in Mathematics 229 (2012), 2868-2887.
Partially ample line bundles on toric varieties. (with N. Broomhead and
Glasgow Math. J. 58 (2016)
boundaries of Hilbert's SOS cones (with G. Blekherman, J. Hauenstein, K. Ranestad
and B. Sturmfels).
Compositio Mathematica 148 (2012).
Components of the Hilbert scheme of space curves on low-degree smooth
surfaces (with J. O. Kleppe).
International Journal of Mathematics Vol. 26, (2015)
ring of a K3 surface of Picard number two.
Journal of Pure
and Applied Algebra
217 (2013), 709-715.
- On the Cox Ring of P2 Blown Up in Points on
Bernt Ivar Utstøl
Simen Westbye Moe
This fall I am teaching MAT4200 - Commutative Algebra.