  The color matrix elements of the ghost triangle diagram that appears in the
triple gluon vertex and the ghost-ghost-gluon triangle diagram that appears in
the ghost-gluon-ghost vertex are calculated. The ghost-ghost-gluon triangle
contains a loop consisting of two color diagonal ghosts and one gluon and a
loop consisting of two color antisymmetric ghosts and one gluon. Consequently,
the pQCD argument in the infrared region based on the one particle irreducible
diagram should be modified. Implications for the Kugo-Ojima color confinement
and the QCD running coupling are discussed.
