• Supertropical linear algebra 

      [OWP-2010-14] Izhakian, Zur; Knebusch, Manfred; Rowen, Louis (Mathematisches Forschungsinstitut Oberwolfach, 2010)
      The objective of this paper is to lay out the algebraic theory of supertropical vector spaces and linear algebra, utilizing the key antisymmetric relation of "ghost surpasses." Special attention is paid to the various ...
    • Supertropical Matrix Algebra III : Powers of Matrices and Generalized Eigenspaces 

      [OWP-2010-20] Izhakian, Zur; Rowen, Louis (Mathematisches Forschungsinstitut Oberwolfach, 2010)
      We investigate powers of supertropical matrices, with special attention to the role of the coefficients of the supertropical characteristic polynomial (especially the supertropical trace) in controlling the rank of a power ...
    • Supertropical Quadratic Forms I 

      [OWP-2013-27] Knebusch, Manfred; Rowen, Louis; Izhakian, Zur (Mathematisches Forschungsinstitut Oberwolfach, 2013)
      We initiate the theory of a quadratic form q over a semiring $R$. As customary, one can write $q(x+y)=q(x)+q(y)+b(x,y)$, where b is a companion bilinear form. But in contrast to the ring-theoretic case, the companion ...
    • Supertropical semirings and supervaluations 

      [OWP-2010-05] Izhakian, Zur; Knebusch, Manfred; Rowen, Louis (Mathematisches Forschungsinstitut Oberwolfach, 2010)
      We interpret a valuation $\upsilon$ on a ring $R$ as a map $\upsilon:R \rightarrow M$ into a so called bipotent semiring $M$ (the usual max-plus setting), and then define a supervaluation $\varphi$ as a suitable map into ...
    • Tensor Representations of q(∞) 

      [OWP-2016-09] Grantcharov, Dimitar; Serganova, Vera (Mathematisches Forschungsinstitut Oberwolfach, 2016-06-17)
      We introduce a symmetric monoidal category of modules over the direct limit queer superalgebra $\mathfrak{q}(\infty)$. The category can be defined in two equivalent ways with the aid of the large annihilator condition. ...
    • Tilting on non-commutative rational projective curves 

      [OWP-2009-14] Burban, Igor; Drozd, Jurij A. (Mathematisches Forschungsinstitut Oberwolfach, 2009-03-08)
      In this article we introduce a new class of non-commutative projective curves and show that in certain cases the derived category of coherent sheaves on them has a tilting complex. In particular, we prove that the right ...
    • Totally Acyclic Complexes 

      [OWP-2016-14] Estrada, Sergio; Fu, Xianhui; Iacob, Alina (Mathematisches Forschungsinstitut Oberwolfach, 2016-08-17)
      We prove first (Proposition 3) that, over any ring $R$, an acyclic complex of projective modules is totally acyclic if and only if the cycles of every acyclic complex of Gorenstein projective modules are Gorenstein projective. ...
    • Varieties of Invariant Subspaces Given by Littlewood-Richardson Tableaux 

      [OWP-2014-01] Kosakowska, Justyna; Schmidmeier, Markus (Mathematisches Forschungsinstitut Oberwolfach, 2014-04-25)
      Given partitions $\alpha, \beta, \gamma$, the short exact sequences $0 \rightarrow N_\alpha \rightarrow N_\beta \rightarrow N_\gamma \rightarrow 0$ of nilpotent linear operators of Jordan types $\alpha, \beta, \gamma$, ...
    • Weighted Surface Algebras: General Version 

      [OWP-2019-07] Erdmann, Karin; Skowroński, Andrzej (Mathematisches Forschungsinstitut Oberwolfach, 2019-02-28)
      We introduce general weighted surface algebras of triangulated surfaces with arbitrarily oriented triangles and describe their basic properties. In particular, we prove that all these algebras, except the singular disc, ...