ar X iv : 0 90 2 . 33 62 v 1 [ m at h . C O ] 1 9 Fe b 20 09 Plücker environments , wiring and tiling diagrams , and weakly separated set - systems

RIMS - 1659 Plücker environments , wiring and tiling diagrams , and weakly separated set - systems

For the ordered set [n] of n elements, we consider the class Bn of bases B of tropical Plücker functions on 2[n] such that B can be obtained by a series of mutations (flips) from the basis formed by the intervals in [n]. We show that these bases are representable by special wiring diagrams and by certain arrangements generalizing rhombus tilings on the n-zonogon. Based on the generalized tiling...

Plücker environments , wiring and tiling diagrams , and weakly separated set - systems

For the ordered set [n] of n elements, we consider the class Bn of bases B of tropical Plücker functions on 2[n] such that B can be obtained by a series of mutations (flips) from the basis formed by the intervals in [n]. We show that these bases are representable by special wiring diagrams and by certain arrangements generalizing rhombus tilings on the n-zonogon. Based on the generalized tiling...

ar X iv : 0 90 2 . 33 48 v 1 [ m at h . R T ] 1 9 Fe b 20 09 On Lie algebras associated with representation directed algebras

Let B be a representation-finite C-algebra. The Z-Lie algebra L(B) associated with B has been defined by Ch. Riedtmann in [17]. If B is representation-directed there is another Z-Lie algebra associated with B defined by C. M. Ringel in [20] and denoted by K(B). We prove that the Lie algebras L(B) and K(B) are isomorphic for any representation-directed C-algebra B. 2000 Mathematics Subject Class...

ar X iv : 0 90 2 . 32 39 v 1 [ m at h . D G ] 1 8 Fe b 20 09 Gauge theory in higher dimensions , II

ar X iv : 0 90 2 . 39 12 v 1 [ m at h . G R ] 2 3 Fe b 20 09 Brent Everitt The Combinatorial Topology