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Dear Gap-forum,

I have placed the file grape-23.g into the directory pub/incoming of

ftp.math.rwth-aachen.de. It contains the GRAPE 2.3 upgrade for the

GRAPE 2.2 share library package. The first lines of the file explain

this upgrade and how to install it, and I reproduce these lines at the

end of this message. As usual, please tell me if you install this

upgrade, and let me know of any problems you solve with it or bugs you

find in it. If you use GRAPE to solve a problem you should still refer

to the paper:

L.H.~Soicher, {\sf GRAPE}: a system for computing with graphs and

groups, in {\it Groups and Computation}, L.~Finkelstein and

W.M.~Kantor, eds., DIMACS Series in Discrete Mathematics and

Theoretical Computer Science {\bf 11}, A.M.S., 1993, pp.~287--291.

I am also planning to write papers on some of the new algorithms in

GRAPE 2.3 (such as PartialLinearSpaces), and the problems I have

solved with them.

This upgrade contains no new on-line documentation, but I have

tried to include very full documentation of the new functions

with their GAP code.

All the best, Leonard Soicher.

First lines of GRAPE 2.3 upgrade:

###############################################################################

##

## grape.g (Version 2.3) GRAPE Library Leonard Soicher

##

##

## Copyright 1992-1996 Leonard Soicher, School of Mathematical Sciences,

## QMW, London, U.K.

##

#

# This file contains the GRAPE 2.3 upgrade to GRAPE 2.2, and contains

# both improvements and new functions. See especially:

# the new CompleteSubgraphsOfGivenSize, which allows for searching in

# a vertex-weighted graph for cliques with a given vertex-weight sum,

# the new function PartialLinearSpaces, which classifies partial linear

# spaces with given point graph and parameters s,t, and the new function

# VertexTransitiveDRGs which determines the distance-regular generalized

# orbital graphs for a given transitive permutation group.

# See also the new functions CayleyGraph and SwitchedGraph.

#

# To install this upgrade to GRAPE 2.2 (on a UNIX system):

# (1) first make sure that GRAPE 2.2 is installed,

# (2) go to the main directory where GAP is installed,

# (3) copy this file to pkg/grape/init.g and also to

# pkg/grape/lib/grape.g

#

# *Notes* As a slight change from GRAPE 2.2, we now consider a one vertex

# graph to be bipartite, with bicomponents = [[],[1]] (to be consistent

# with considering a zero vertex graph to be bipartite, with

# bicomponents = [[],[]]). This upgrade also fixes a bug in UnderlyingGraph

# which had the effect that if the returned graph had loops, then it

# might have had its isSimple component erroneously set to true.

#

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