On Saturday, 22 September 2012 23:33:54 UTC+1, Gordon Sande wrote:
> > Let S be the set of indices you want. The you can talk about its > > entries as subscripted > > values. To get the rows of A you then needed subscripted subscripts. > > The question is where > > do you do the colapsing. S does the job!
Thanks - but how do I actually write this as a maths expression that will satisfy what the referee requires ? I am afraid I am a physicist, not a mathematician .... cheers, Beau