[seqfan] Mathematical notation

franktaw at netscape.net franktaw at netscape.net
Thu Sep 3 02:13:33 CEST 2009

Very interesting article.

I have a notational convenience of my own that I much prefer to the 
standard notation.  Instead of writing, for example, Q^+ (that is, Q 
with a superscript plus sign) for the positive rationals, I prefer to 
write Q^> (Q with a superscript greater than).

The advantage of this is that I can then write Q^>= (Q with a 
superscript greater than or equal) for the non-negative rationals; and 
this is MUCH more convenient than Q^+ U {0}.  Likewise, Q^!= (Q 
superscript not equal) is the non-zero rationals -- instead of Q - {0} 
or Q^+ U Q^-.  (Q^= for {0} doesn't seem very useful, however.)

In the case of Z for the integers, there is the alternate notation N.  
However, there seems to be some ambiguity as to whether N is supposed 
to represent Z^> or Z^>=.

Franklin T. Adams-Watters

-----Original Message-----
From: Edwin Clark <eclark at math.usf.edu>

The discussion in the paper: "Two Notes on Notation"
by Donald Knuth at


may cast some light on this subject. Although several
of the points made in this paper were already mentioned
in previous discussions in this thread.

See particularly the discussion on page 6.

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