Re: Slightly cheaper elephants?

[Vaughan Pratt <pratt@CS.Stanford.EDU>]

In my previous post under this subject line I asked two questions.

>First, are other sources of "Elephant" at 17% or better off Amazon's $295.00
>price available to us eager students of toposophy?

As it turns out, OUP is happy to offer 20% off this book for AMS, SIAM,
and LMS members.

As an AMS member I have suddenly forgotten what the second question was.

I hereby bequeath to nonmembers of the aforesaid societies my little theorem
about Amazon discounts, that for any bulk purchase accomplished within a
week, with Amazon handling both billing and distribution (separate shipping
addresses for each book), purchase of n+1 copies of the same book nets a
total discount of 20n% (n/5) for the n+1 purchasers, that is, n/(5*(n+1))
per purchaser.

Amazon distributes n/10 of this to the first purchaser and 1/10 to each of
the remaining n purchasers.

With Amazon's system, the first purchaser breaks even at the second purchase
(each purchaser nets 10%) and draws ahead with the third (the first purchaser
gets 20% and the other two 10%).

A group organizing for this purpose may prefer a completely equitable system,
in which each of the n+1 parties receives a discount of n/(5*(n+1)) (20%
of n/(n+1)).  Complete parity should therefore be achieved when the first
purchaser distributes n/(5*(n+1)) - 1/10 = (n-1)/(10*(n+1)) to each of the
other purchasers, but read Amazon's "Share the Love" rules in full before
ordering the first book.  Bear in mind that Amazon offers free shipping to
those not in a tearing hurry for knowledge.

A first purchaser with a taste for simplicity and a gambling spirit may wish
to offer a flat 1/6 discount to each of the other purchasers, keeping n/30 of
the remainder.  Breakeven in this scheme is at n=5 (a total of 6 purchasers).
I was close to that point when OUP's Alison Jones (Jonesal@oup.co.uk) answered
my first question in the affirmative, whom members of the aforementioned
societies should contact with their orders (if I have correctly interpreted
her emails to me on the subject, which seemed clear enough).

While all this may seem a bit hard on nonmembers of these societies, for
whom n could be advantageously larger if the members joined in this plan,
rest assured that the patiently supportive members of these worthy and
worthwhile academic societies do not feel your pain.

One other disadvantage of ordering from Amazon is that they appear to know
only about the 2-volume set of 1600 pages at $295, and not the higher-priced
individual volumes, for which one would expect Amazon to ask perhaps $170 each
were they to offer them.  If you aren't Superman planning to read and absorb
the whole 1600 pages in one speed-reading pass, and didn't need something
more substantial than the phone directory to stand on when rescuing the
cat off the top china shelf, you might wish to consider the ergonomic and
durability benefits of two separate volumes, the higher cost notwithstanding.

I do hope Peter J. does reasonably well off all this, heaven knows he's
worked hard enough and insightfully enough for it.

Vaughan