John Christian Ottem

Bilde av John Christian Ottem
English version of this page
Telefon +47 22855930
Rom 1109
Brukernavn
Besøksadresse Moltke Moes vei 35 Niels Henrik Abels hus 0851 Oslo
Postadresse Postboks 1053 Blindern 0316 Oslo

Personal webpage

CV

Research interests

Higher dimensional algebraic geometry, positivity of line bundles and subschemes, Calabi-Yau manifolds, and the moduli space of curves.

Projects

'Young Research Talents'. Research Council of Norway 2016-2021.

Teaching

This term I am teaching MAT1110 - Calculus and linear algebra and MAT4215 - Algebraic Geometry II.

Students

Bernt Ivar Utstøl Nødland (2016-2019)
Bjørn Skauli (2018-)
Martin Helsø (2017-, co-advisor)
Elisa Cazzador (2018-, co-advisor)
Simen Westbye Moe (2019-)

Publications

  1. An O-acyclic variety of even index (with F. Suzuki) (2020)

  2. A refinement of the motivic volume, and specialization of birational types (with J. Nicaise) (2020)

  3. Two coniveau filtrations (with O. Benoist) (2020)

  4. Tropical degenerations and stable rationality (Updated version: Oct 2020) (with J. Nicaise) (2019) Video 1 Video 2 Video 3

  5. A pencil of Enriques surfaces with non-algebraic integral Hodge classes (with F. Suzuki) Mathematische Annalen 377 (2020), 183–197. Video

  6. On deformations of quintic and septic hypersurfaces (with S. Schreieder) Journal de Mathématiques Pures et Appliquées 135 (2020), 140-158.

  7. Remarks on the positivity of the cotangent bundle of a K3 surface (with F. Gounelas) Épijournal de Géométrie Algébrique 4 (2020).

  8. Curve classes on irreducible holomorphic symplectic varieties (with G. Mongardi) Communications in Contemporary Mathematics (2020)

  9. Failure of the integral Hodge conjecture for threefolds of Kodaira dimension zero (with O. Benoist). Commentarii Mathematici Helvetici 95 (2020) 27-35.

  10. 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

  11. Positivity of the diagonal (with B. Lehmann). Advances in Mathematics 335 (2018), 664-695.

  12. Nef cycles on some hyperkahler fourfolds. Facets of Algebraic Geometry: A Volume in Honour of William Fulton's 80th Birthday', LMS Lecture Note Series (to appear).

  13. Effective cones of cycles on blow-ups of projective space (with I. Coskun, J. Lesieutre). Algebra & Number Theory 10-9 (2016).

  14. Curves disjoint from a nef divisor (with J. Lesieutre). Michigan Mathematical Journal 65 (2016), 321-332.

  15. On subvarieties with ample normal bundle. Journal of the European Mathematical Society 18 (2016), 2459-2468

  16. Birational geometry of hypersurfaces in products of projective spaces. Mathematische Zeitschrift 280 (2015), 135-148

  17. Partially ample line bundles on toric varieties. (with N. Broomhead and A. Prendergast-Smith). Glasgow Math. J. 58 (2016)

  18. Quartic spectrahedra (with K. Ranestad, B. Sturmfels, C. Vinzant) Mathematical Programming 151 (2), 585-612 (2015).

  19. Ample subvarieties and q-ample divisors. Advances in Mathematics 229 (2012), 2868-2887.

  20. Components of the Hilbert scheme of space curves on low-degree smooth surfaces (with J. O. Kleppe). International Journal of Mathematics Vol. 26, (2015)

  21. Algebraic boundaries of Hilbert's SOS cones (with G. Blekherman, J. Hauenstein, K. Ranestad and B. Sturmfels). Compositio Mathematica 148 (2012).

  22. The Cox ring of a K3 surface of Picard number two. Journal of Pure and Applied Algebra 217 (2013), 709-715.

  23. On the Cox Ring of P2 Blown Up in Points on a Line. Mathematica Scandinavica 9, (2011), 21-31.

Other

Publikasjoner

  • Ottem, John Christian; Itenberg, Ilia & Degtyarev, Alex (2023). Planes in cubic fourfolds . Algebraic Geometry. ISSN 2313-1691.
  • Ottem, John Christian & Nicaise, Johannes (2022). Tropical degenerations and stable rationality . Duke mathematical journal. ISSN 0012-7094. doi: https%3A/doi.org/10.1215/00127094-2022-0065.
  • Nicaise, Johannes & Ottem, John Christian (2021). A refinement of the motivic volume, and specialization of birational types. Progress in Mathematics. ISSN 0743-1643. 342, s. 299–322. doi: 10.1007/978-3-030-75421-1. Fulltekst i vitenarkiv
  • Benoist, Olivier & Ottem, John Christian (2021). Two coniveau filtrations . Duke mathematical journal. ISSN 0012-7094. 170(12), s. 2719–2753. doi: 10.1215/00127094-2021-0055. Fulltekst i vitenarkiv
  • Gounelas, Frank & Ottem, John Christian (2020). Remarks on the positivity of the cotangent bundle of a K3 surface. Épijournal de Géométrie Algébrique (EPIGA). ISSN 2491-6765. 4(8). doi: 10.46298/epiga.2020.volume4.5924. Fulltekst i vitenarkiv
  • Benoist, Olivier & Ottem, John Christian (2020). Failure of the integral Hodge conjecture for threefolds of Kodaira dimension zero . Commentarii Mathematici Helvetici. ISSN 0010-2571. 95, s. 27–35. doi: 10.4171/CMH/479. Fulltekst i vitenarkiv
  • Ottem, John Christian & Suzuki, Fumiaki (2020). A pencil of Enriques surfaces with non-algebraic integral Hodge classes. Mathematische Annalen. ISSN 0025-5831. 377, s. 183–197. doi: 10.1007/s00208-020-01969-8. Fulltekst i vitenarkiv
  • Ottem, John Christian (2020). Nef cycles on some hyperkähler fourfolds. arXiv.org. ISSN 2331-8422.
  • Mongardi, Giovanni & Ottem, John Christian (2019). Curve classes on irreducible holomorphic symplectic varieties. Communications in Contemporary Mathematics. ISSN 0219-1997. 22(7). doi: 10.1142/S0219199719500780. Fulltekst i vitenarkiv
  • Ottem, John Christian & Schreieder, Stefan (2019). On deformations of quintic and septic hypersurfaces. Journal des Mathématiques Pures et Appliquées. ISSN 0021-7824. 135. doi: 10.1016/j.matpur.2019.12.013. Fulltekst i vitenarkiv
  • Mongardi, Giovanni & Ottem, John Christian (2019). Curve classes on irreducible holomorphic symplectic varieties . arXiv.org. ISSN 2331-8422. doi: 10.1142/S0219199719500780.
  • Ottem, John Christian & Gounelas, Frank (2018). Remarks on the positivity of the cotangent bundle of a K3 surface . arXiv.org. ISSN 2331-8422.
  • Ottem, John Christian & Benoist, Olivier (2018). Failure of the integral Hodge conjecture for threefolds of Kodaira dimension zero . Commentarii Mathematici Helvetici. ISSN 0010-2571. doi: 10.4171/cmh/479.
  • Ottem, John Christian & Schreieder, Stefan (2018). On deformations of quintic and septic hypersurfaces . arXiv.org. ISSN 2331-8422. doi: 10.1016/j.matpur.2019.12.013.
  • Ottem, John Christian & Rennemo, Jørgen Vold (2018). A counterexample to the birational Torelli problem for Calabi-Yau 3-folds. Journal of the London Mathematical Society. ISSN 0024-6107. 97(3), s. 427–440. doi: 10.1112/jlms.12111. Fulltekst i vitenarkiv
  • Lehmann, Brian & Ottem, John Christian (2018). Positivity of the diagonal. Advances in Mathematics. ISSN 0001-8708. 335, s. 664–695. doi: 10.1016/j.aim.2018.07.002. Fulltekst i vitenarkiv
  • Coskun, Izzet; Lesieutre, John & Ottem, John Christian (2016). Effective cones of cycles on blowups of projective space. Algebra & Number Theory. ISSN 1937-0652. 10(9), s. 1983–2014. doi: 10.2140/ant.2016.10.1983.
  • Ottem, John Christian (2016). On subvarieties with ample normal bundle. Journal of the European Mathematical Society (Print). ISSN 1435-9855. 18(11), s. 2459–2468. doi: 10.4171/JEMS/644. Fulltekst i vitenarkiv
  • Ottem, John Christian; Prendergast-Smith, Artie & Broomhead, Nathan (2016). Partially ample line bundles on toric varieties. Glasgow Mathematical Journal. ISSN 0017-0895. 58(3), s. 587–598. doi: 10.1017/S001708951500035X.
  • Lesieutre, John & Ottem, John Christian (2016). Curves disjoint from a nef divisor. The Michigan mathematical journal. ISSN 0026-2285. 65(2), s. 321–332. doi: 10.1307/mmj/1465329015.
  • Ottem, John Christian (2015). Birational geometry of hypersurfaces in products of projective spaces. Mathematische Zeitschrift. ISSN 0025-5874. 280(1), s. 135–148. doi: 10.1007/s00209-015-1415-x.
  • Kleppe, Jan Oddvar & Ottem, John Christian (2015). Components of the Hilbert scheme of space curves on low-degree smooth surfaces . International Journal of Mathematics. ISSN 0129-167X. 26(2). doi: 10.1142/S0129167X15500172. Fulltekst i vitenarkiv
  • Ottem, John Christian (2013). Cox rings of K3 surfaces with Picard number 2. Journal of Pure and Applied Algebra. ISSN 0022-4049. 217(4), s. 709–715. doi: 10.1016/j.jpaa.2012.09.016. Fulltekst i vitenarkiv
  • Blekherman, Grigoriy; Hauenstein, Jonathan; Ottem, John Christian; Ranestad, Kristian & Sturmfels, Bernd (2012). Algebraic boundaries of Hilbert's SOS cones. Compositio Mathematica. ISSN 0010-437X. 148(6), s. 1717–1735. doi: 10.1112/S0010437X12000437. Fulltekst i vitenarkiv
  • Ottem, John Christian (2012). Ample subvarieties and q-ample divisors. Advances in Mathematics. ISSN 0001-8708. 229(5), s. 2868–2887. doi: 10.1016/j.aim.2012.02.001.
  • Ottem, John Christian (2011). ON THE COX RING OF P-2 BLOWN UP IN POINTS ON A LINE. Mathematica Scandinavica. ISSN 0025-5521. 109(1), s. 22–30. doi: 10.7146/math.scand.a-15175. Fulltekst i vitenarkiv

Se alle arbeider i Cristin

  • Ottem, John Christian (2021). Enriques surface fibrations with even index.
  • Ottem, John Christian (2021). Tropical degenerations and stable rationality.
  • Ottem, John Christian & Ottem, John Christian (2021). Enriques surface fibrations with even index.
  • Ottem, John Christian (2021). Tropical degenerations and stable rationality.
  • Ottem, John Christian (2021). Tropical degenerations and stable rationality.
  • Ottem, John Christian (2020). Tropical degenerations and stable rationality.
  • Ottem, John Christian (2020). On (2,3)-fourfolds.
  • Ottem, John Christian (2020). Tropical degenerations and stable rationality.
  • Ottem, John Christian (2019). Counterexamples to the integral Hodge conjecture.
  • Ottem, John Christian (2019). Counterexamples to the integral Hodge conjecture.
  • Ottem, John Christian (2019). Deformations of hypersurfaces.
  • Ottem, John Christian (2019). A counterexample to the birational Torelli problem.
  • Ottem, John Christian (2019). A pencil of Enriques surfaces with non-algebraic integral Hodge classes.
  • Ottem, John Christian (2019). A pencil of Enriques surfaces with non-algebraic integral Hodge classes.
  • Ottem, John Christian (2018). Failure of the Integral Hodge conjecture for 3-folds.
  • Ottem, John Christian (2018). Integral hodge conjecture for holomorphic symplectic varieties.
  • Ottem, John Christian (2018). Integral Hodge conjecture for threefolds.
  • Ottem, John Christian (2018). The integral Hodge conjecture for threefolds.
  • Ottem, John Christian (2018). Positivity of the higher codimension cycles.
  • Ottem, John Christian (2018). Integral Hodge conjecture for threefolds.
  • Ottem, John Christian (2018). The birational Torelli problem for Calabi-Yau 3-folds.
  • Ottem, John Christian (2017). A counterexample to the birational Torelli problem for Calabi Yau threefolds.
  • Ottem, John Christian (2017). A counterexample to the birational Torelli problem for Calabi-Yau threefolds.
  • Ottem, John Christian (2017). Nef cycles of higher codimension.
  • Ottem, John Christian (2017). Semiample line bundles in positive characteristic.
  • Ottem, John Christian (2017). Nef cycles on some hyperkahler fourfolds.
  • Ottem, John Christian (2017). Nef cycles on some hyperkahler fourfolds.
  • Ottem, John Christian (2017). Nef cycles on some hyperkahler manifolds.
  • Ottem, John Christian (2017). Nef cycles on some hyperkahler manifolds.
  • Ottem, John Christian (2017). Positivity of the diagonal.
  • Ottem, John Christian (2017). Positivity of the diagonal.
  • Ottem, John Christian (2017). The Birational Torelli problem for Calabi-Yau 3-folds.
  • Ottem, John Christian (2017). Positivity of the diagonal.
  • Ottem, John Christian (2016). Effective cycles of higher codimension.
  • Ottem, John Christian (2016). Positivity in higher codimension.
  • Ottem, John Christian (2016). Nef cycles on hyperkahler manifolds.
  • Ottem, John Christian (2016). Effective cones of cycles on blow-ups of projective space.
  • Ottem, John Christian (2016). Effective cycles on blow-ups of projective space.
  • Ottem, John Christian (2016). Moduli of K3s via Global Torelli.
  • Ottem, John Christian (2016). Effective cones of cycles on blow-ups of projective space.
  • Ottem, John Christian (2016). Effective and nef cycles in higher codimension.
  • Ottem, John Christian (2016). Higher codimension cycles.
  • Ottem, John Christian (2016). K3 surfaces.
  • Kleppe, Jan Oddvar & Ottem, John Christian (2012). Components of the Hilbert scheme of space curves on low-degree smooth surfaces. arXiv:1204.4819 [math.AG].

Se alle arbeider i Cristin

Publisert 6. jan. 2016 09:09 - Sist endret 7. sep. 2022 11:15

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