Some new bounds for the maximum length of circuit codes (Corresp.)

A
d
-dimensional circuit code of spread
s
is a simple circuit
C
in the graph of the
d
-dimensional unit cube with the property that for any vertices
x
and
y
of
C
that differ in exactly
r
coordinates
r < s
, there exists a path from
x
to
y
consisting of
r
edges of
C
. Some new lower bounds will be given for the maximum length of a
d
-dimensional circuit code of spread
s
for some values of
d
and for
s = 4, s = 6
, and
s = 7
.