19 citations · 20 across the 3 of their papers we have counts for
4 papers
Counting covering cycles
G. A. T. F da Costa, M. Policarpo
We compute the number of equivalence classes of nonperiodic covering cycles of given length in a non oriented connected graph. A covering cycle is a closed path that traverses each…
Graphs and Generalized Witt identities
G. A. T. F. da Costa
This paper is about the determinantal identities associated with the Ihara (Ih) zeta function of a non directed graph and the Bowen-Lanford (BL) zeta function of a directed graph.…
On the Nonlocal Equations and Nonlocal Charges Associated with the Harry Dym Hierarchy
J. C. Brunelli, G. A. T. F. da Costa
A large class of nonlocal equations and nonlocal charges for the Harry Dym hierarchy is exhibited. They are obtained from nonlocal Casimirs associated with its bi-Hamiltonian struc…
Non-Trivial Non-Canonical W-Algebras from Kac-Moody Reductions
G. A. T. F. da Costa, L. O'Raifeartaigh
By reducing a split Kac-Moody algebra by a non-maximal set of first-class constraints we produce W-algebras which (i) contain fields of negative conformal spin and (ii) are n…