%0 Report %D 2013 %T Symplectic instanton bundles on P3 and 't Hooft instantons %A Ugo Bruzzo %A Dimitri Markushevich %A Alexander Tikhomirov %X We introduce the notion of tame symplectic instantons by excluding a kind of pathological monads and show that the locus $I^*_{n,r}$ of tame symplectic instantons is irreducible and has the expected dimension, equal to $4n(r+1)-r(2r+1)$. The proof is inherently based on a relation between the spaces $I^*_{n,r}$ and the moduli spaces of 't Hooft instantons. %I arXiv:1312.5554 [math.AG] %G en %U http://urania.sissa.it/xmlui/handle/1963/34486 %1 34675 %2 Mathematics %4 1 %# MAT/03 %$ Submitted by Ugo Bruzzo (bruzzo@sissa.it) on 2015-08-07T20:57:05Z No. of bitstreams: 1 Symplectic_instantons_II-rev-dec2014.pdf: 340035 bytes, checksum: 8d0a2dfeea126810645c06e8b6352903 (MD5) %0 Journal Article %J Central European Journal of Mathematics 10, nr. 4 (2012) 1232 %D 2012 %T Moduli of symplectic instanton vector bundles of higher rank on projective space $\\mathbbP^3$ %A Ugo Bruzzo %A Dimitri Markushevich %A Alexander Tikhomirov %X Symplectic instanton vector bundles on the projective space $\\mathbb{P}^3$ constitute a natural generalization of mathematical instantons of rank 2. We study the moduli space $I_{n,r}$ of rank-$2r$ symplectic instanton vector bundles on $\\mathbb{P}^3$ with $r\\ge2$ and second Chern class $n\\ge r,\\ n\\equiv r({\\rm mod}2)$. We give an explicit construction of an irreducible component $I^*_{n,r}$ of this space for each such value of $n$ and show that $I^*_{n,r}$ has the expected dimension $4n(r+1)-r(2r+1)$. %B Central European Journal of Mathematics 10, nr. 4 (2012) 1232 %I SISSA %G en %U http://hdl.handle.net/1963/4656 %1 4406 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Maria Pia Calandra (calapia@sissa.it) on 2011-10-10T09:47:24Z\r\nNo. of bitstreams: 1\r\n1109.2292v1.pdf: 243006 bytes, checksum: 39feac60657ccc939b3d688db3738e0e (MD5) %R 10.2478/s11533-012-0062-2 %0 Journal Article %J Doc. Math. 16 (2011) 399-410 %D 2011 %T Moduli of framed sheaves on projective surfaces %A Ugo Bruzzo %A Dimitri Markushevich %X We show that there exists a fine moduli space for torsion-free sheaves on a\\r\\nprojective surface, which have a \\\"good framing\\\" on a big and nef divisor. This\\r\\nmoduli space is a quasi-projective scheme. This is accomplished by showing that such framed sheaves may be considered as stable pairs in the sense of\\r\\nHuybrechts and Lehn. We characterize the obstruction to the smoothness of the moduli space, and discuss some examples on rational surfaces. %B Doc. Math. 16 (2011) 399-410 %I Documenta Mathematica %G en %U http://hdl.handle.net/1963/5126 %1 4942 %2 Mathematics %3 Mathematical Physics %4 -1 %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2011-11-28T15:59:58Z\\nNo. of bitstreams: 1\\n0906.1436v2.pdf: 285229 bytes, checksum: 6451a4aeb6a764184842f8515fec4930 (MD5) %0 Report %D 2010 %T Uhlenbeck-Donaldson compactification for framed sheaves on projective surfaces %A Ugo Bruzzo %A Dimitri Markushevich %A Alexander Tikhomirov %X We construct a compactification $M^{\\\\mu ss}$ of the Uhlenbeck-Donaldson type for the moduli space of slope stable framed bundles. This is a kind of a moduli space of slope semistable framed sheaves. We show that there exists a projective morphism $\\\\gamma \\\\colon M^s \\\\to M^{\\\\mu ss}$, where $M^s$ is the moduli space of S-equivalence classes of Gieseker-semistable framed sheaves. The space $M^{\\\\mu ss}$ has a natural set-theoretic stratification which allows one, via a Hitchin-Kobayashi correspondence, to compare it with the moduli spaces of framed ideal instantons. %G en_US %U http://hdl.handle.net/1963/4049 %1 353 %2 Mathematics %3 Mathematical Physics %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2010-09-08T08:00:00Z\\nNo. of bitstreams: 1\\nBruzzo59FM.pdf: 496341 bytes, checksum: 3e67e590463152505d393721e3a2c10a (MD5)