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Florida International University

Florida International University

Title: Lie Algebras and Geometric Structures for Undergraduates


  • Gueo Grantcharov
  • Mirroslav Yotov


Dates of Program: May 9 - June 17, 2011


This proposed project will study a relation between Linear Algebra and Graph Theory with a view toward Differential Geometric applications. In 2004, S. Dani and M. Miankar associated to a directed graph a two-step nilpotent Lie algebra in a pretty easy way: For any such graph with vertices V = {v1, . . . , vn} and edges E, we assign vector spaces W and U, such that W has a basis w1, ...,wn corresponding to the elements in V and U ’ Î?2V is generated by wij = wi â?§ wj , where wiwjE. A Lie bracket on WU is defined in the following way:

[wi,wj] = wij = -[wj ,wi]

if vivj is an edge and all other brackets of the generators are zero.
M. Miankar proved recently that two such 2-step nilpotent Lie algebras are isomorphic iff their corresponding graphs are isomorphic. The students participating in the project will explore further the construction above concentrating on two main problems. The first one is about extending the categorical properties of the relation beyond the statement above. A natural question here is whether there is an additional category structure on the set of graphs for which the correspondence is a functor into the category of Lie algebras. Also how to characterize the algebras corresponding to particular types of graphs, such as bipartite, Eulerian, Hamiltonian, k-connected etc. graphs. The second problem is to relate various geometric structures on Lie algebras and the corresponding nilmanifolds to their graph counterparts. The geometric structures to be considered are complex, symplectic, hypercomplex, para-hypercomplex and hypersymplectic. These structures appear in theoretical physics and are objects of constant interest for mathematicians and physicists. On the other hand, they are easily described in terms of tensors on the Lie algebra of vector fields of the manifold, and are appropriate objects for investigation within the context of the project.

Student Researchers Supported by MAA:

  • Lazaro Diaz
  • Omar Jesus Leon
  • Alexander Moncion
  • Austin Nowak

More Information:

Program Contacts:

Bill Hawkins

Michael Pearson
MAA Programs & Services