Binomial transforms, floretions, and a divisors property

Creighton Dement crowdog at crowdog.de
Tue Sep 13 23:06:08 CEST 2005


Dear Seqfans, 

The binomial transform of a sequence ((a(n)) is defined as  b(n)=SUM
C(n,k)a(k), k=0..n

Let x = x_0'i + x_1'j + x_2'k} + x_3i' + x_4j' + x_5k' + x_6'ii' +
x_7'jj' + x_8'kk' + x_9'ij' + x_{10}'ik' + x_{11}'ji' + x_{12}'jk' +
x_{13}'ki' + x_{14}'kj' + x_{15}e be a member of the floretion algebra
over the reals such that a(n) = tes[x^(n+1)] is an integer for all n >=
0. "tes" is defined as tes(x) = x_{15}. Further define tesseq[x] =
(tes[x^(1)], tes[x^(2)], tes[x^(3)], ) and x^0 = e. 

Conjecture: If a' = (1, a(0), a(1), ) = (1, tes[x], tes[x^2], ) is an
integer sequence then  b' = (1, b(0), b(1), b(2), ) = (1, tes[x+e],
tes[(x+e)^2, ) is the binomial transform of a'. 


Proof. tes is a linear mapping. Moreover, x and the unit e commute.
Thus,   
SUM C(n,k)a'(k), k=0..n = SUM C(n,k)tes[x^(k)], k=0..n 
= tes[SUM C(n,k)x^k], k=0..n 
= tes[(x+e)^k], k=0..n 
= b', q.e.d.


This is actually somthing which has confused me for a long time: Why was
tesseq[x+1] sometimes but not always the binomial transform of
tesseq[x]? I figured the reason must have lain really deep and just
tried my best to work around it. It now seems it was all just a matter
of how I'd defined the initial term
of the sequence tesseq[x] = (tes[x], tes[x^2], tes[x^3], tes[x^4],
tes[x^5], ) *not* 
tesseq[x] = (tes[x^0], tes[x^1], tes[x^2]. )


One more idea I had today which could be -if it should work-
interesting.

A conjecture I made in a previous post to the 
seqfan list (I believe under the heading "Mersenne numbers and the
divisors property" ) was that if (a(n)) satisfies a linear 2nd order
recurrence relation, then if s divides a(m) and s divides a(n) then s
also divides a(2n-m)  for n > m (I also posted this same question to
sci.math.)  My idea: try to reformulate the question so that it asks
about a property of floretions, instead.   

What would a "floretion proof" of this property look like? 

Here is a quick list of some of the conjectures made:
Define E =  + .25'i + .25i' + .25'ii' + .25'jj' + .25'kk' + .25'jk' +
.25'kj' + .25e
Use FAMP to show that E^2 = F = .25'ii' + .25'jj' + .25'kk' + .25e and
F^2 = F. 

Conjecture (MAIN): If tesseq[x] is an integer sequence then tesseq[x]
satisfies a linear 4th order recurrence relation or less. 
 
Conjecture II: If tesseq[x] is an integer sequence then tesseq[E*x]
satisfies a 
linear 2nd order recurrence relation. It appears there exists at least
one second element D (which is not related to E by some cyclic
transformation) with this same property.   

Proposition:
If x and y are floretions, then tesseq[x*y] = tesseq[y*x] (a proof of
this simple but important property, in my opinion, has been found). 

Question is: how "big" is the set of 2nd order sequences generated the
sequences tesseq[E*x] (or tesseq[D*x]? In any case, it will apparently
be possible to show that the set is not trivial.

  
A question related to (and/or equivilant to- depending on how big the
set of sequences is) the one above in terms of floretions is:

If s | tes[(E*x)^m] and s | tes[(E*x)^n] does it also follow that s |
tes[(E*x)^(2*m - n)]? This, in turn, could make it possible to use some
of the conjectures, above. To demonstrate the point with a wild example,
we might find that "all we really have left to show" is: If y is a
floretion such that s | tes[E*y] then s | tes[E*y^2] (or some similar
property) - showing these would presumably be much easier than the
original problem. Of course, we would still have all the conjectures
from above to prove.   


Sincerely, 
Creighton 







More information about the SeqFan mailing list