C. Goffman and G. N. Wollan
conjectured that the bounded summability field of a regular matrix A is so thin that
the union of countably many such sets is not dense in m. G. M. Petersen proved this
conjecture. This result is strengthened by showing if A is a noncoercive matrix whose
summability field contains all the finite sequences then its bounded summability field
is so thin that the union of countably many such sets is not dense in m. An
example is given to show that the condition of containing the finite sequences is
necessary.