A new version of my commutative diagrams package is now available. Users of the version released last September will know that it uses a matrix syntax for the objects and morphisms, and is able to stretch horizontal arrows to meet the objects at the endpoints. The new version is also able to stretch verticals, and the diagonals have been re-worked. Those who have Mike Barr's package will recognise the following diagram from his manual, or from the errata to Toposes, TRiples and Theories which he circulated on 25 April. BITNET users suffering gross corruption may like to know that "\rArr?\mu" has a caret (superscript) symbol in the middle, whilst "\dArr^?\sigma TT'?" (following 4) has a tilde. $$\CellSize=4em \diagram TT & \rArr^\mu & T \\ & \SE_{TT\eta'} & 1 & \SE^{T\eta} \\ \dArr^{T\eta'T} & 2 & TTT' &\pile{ \rArr^{\mu T'}\\ \rArr_{T\sigma}} & TT' \\ & & \dArr^{T\eta'TT' }& 3 & \dArr^{T\eta'T'} & \llap{6\quad}\SE^{id} \\ TT'T &\rArr^{TT'T\eta'}& TT'TT' &\rArr^{TT'\sigma}& TT'T' & \rArr^{T\mu'}&TT'\\ \dArr^{\sigma T} & 4 & \dArr~{\sigma TT'}& 5 & \dArr~{\sigma T'}& 7 & \dArr_\sigma \\ T'T & \rArr_{T'T\eta'} & T'TT' & \rArr_{T'\sigma} & T'T' & \rArr_{\mu'} & T'\\ \enddiagram$$ Paper copies of the manual for my package will be available at Como, and I shall dispatch electronic copies of the package & manual just before I depart for Italy myself (to allow for last minute bug-fixes while I print my own papers!). Known past users should get it automatically, but to be sure, please email me, including the word "diagrams" in your subject line. Paul Taylor, Dept. of Computing, Imperial College, London SW7 2BZ, UK email pt@doc.ic.ac.uk pt%ic.doc@ukacrl or ...!mcvax!ukc!icdoc!pt phone +44 71 589 5111 x 5057 fax +44 71 581 8024 *************** PS LONDON PHONE NUMBERS HAVE CHANGED *******************