ADDITION.
On p. 416, the parameter set for a bipartite distance-regular
graph on 686 vertices of diameter 6 has been ruled out by
J.H. Koolen (May 1991) by observing that it must contain
a non-integral number of Pappus subgraphs.
CORRECTION.
On p. 417-418, in the four places where it is stated for a graph
$GAM$ of diameter 5 that `$GAM sub 1,2$ is strongly regular', change
this into `$GAM sub 1,2$ is distance-regular'.
(This occurs for primitive graphs on 462 and 1024 vertices, and for
bipartite antipodal graphs on 20 and 32 vertices.)
CORRECTION.
On p. 418, delete lines 5-6. (Indeed, on p. 160 it was already
mentioned that the parameter set $v = 2912$, intersection array
$"{"105,90,49,7,1;1,7,49,90,105"}"$ was ruled out by Theorem 4.4.4.)
For the same reason, the six parameter sets
$"{"36,25,8;1,4,20"}"$ (on p. 428),
$"{"72,45,16;1,8,54"}"$, $"{"85,54,25;1,10,45"}"$,
$"{"90,60,12;1,12,72"}"$ (on p. 430),
$"{"112,77,16;1,16,88"}"$ and $"{"145,84,25;1,20,105"}"$ (on p. 431)
can be deleted.
ADDITION.
On p. 419, the parameter set $"{"5,4,3,3;1,1,1,2"}"$ $(v = 176)$
can be deleted; the nonexistence of a corresponding graph was
shown in
.SC Fon-Der-Flaass
.[[
Fon-Der-Flaass exist no176
.]].
ADDITION.
On p. 422, the parameter set $"{"45,40,11,1;1,1,40,45"}"$
can be deleted (its singular lines are too large), and
of the five parameter sets $"{"56,45,24- mu ,1;1, mu ,45,56"}"$
the four with $mu != 8$ may be deleted, while there is a unique
graph when $mu = 8$ (the Soicher graph, see \(sc11.4I above).
ADDITION.
On p. 424, the question marks for the parameter sets
$"{"176,135,24,1;1,24,135,176"}"$ and
$"{"176,135,36,1;1,12,135,176"}"$ can be deleted;
according to Soicher [pers. comm.] the collinearity graphs
of the two geometries constructed in
.SC Meixner
.[[
Meixner polar towers
.]],
Proposition 4.3, are distance-transitive antipodal 2- and 4-covers
of the strongly regular graph on the nonisotropic points in $U(6,2 sup 2 )$
(nonadjacent when joined by a tangent).
ADDITION.
On p. 425, the parameter set $"{"5,4,3;1,1,2"}"$ $(v = 56)$
can be deleted; the nonexistence of a corresponding graph was
shown in
.SC Fon-Der-Flaass
.[[
Fon-Der-Flaass exists no56
.]].
ADDITION.
Below we give tables for bipartite but not antipodal distance-regular
graphs of diameter 4. They belong on p. 425.
CORRECTION.
On p. 427, the $7 sup {roman "th"}$ parameter set
(starting $v = 525 = 1 + 20 + ...$) is known; an example is
the unitary nonisotropics graph for $q = 5$ (cf. \(sc12.4).
ADDITION.
On p. 427, the $7 sup {roman "th"}$ parameter set from below
(starting $v = 729 = 1 + 26 + ...$) is known; an example is
given by one of the graphs discussed in the (new) Section \(sc12.8
(for $q = 3$).
On p. 428, the $8 sup {roman "th"}$ parameter set (starting
$v = 1024 = 1 + 31 + ...$) is known; an example is given by
a Kasami graph, cf. Theorem 11.2.1 (13), with $q = j = 2$.
CORRECTION.
On p. 431, line -11, delete `(with the same parameters as $GAM$)'.
ADDITION.
On p. 431, last line, add: `See also
.SC Gardiner
.[[
Gardiner antipodal coverings 1990
.]]'.