Keywords: crank, j-times, vector partitions, weight, exponent
Turkish Journal of Analysis and Number Theory, 2014 2 (4),
pp 125-129.
DOI: 10.12691/tjant-2-4-4
Received April 04, 2014; Revised June 14, 2014; Accepted July 31, 2014
Copyright © 2013 Science and Education Publishing. All Rights Reserved.
1. Introduction
First we give definitions of
, the crank of partitions,
,
,
and
. We generate some generating functions related to the crank and show the coefficient of x is the algebraic relations in terms of various powers of z, the exponent of z represent the crank of partitions of n (for all
). We show the results with the help of examples when n = 5 and 6 respectively. We introduce the special term weight
related to the vector partitions V and show the relations in terms of
, weight
and crank
. We prove the Theorem “The number of partitions
of n with crank
is
for all
.”
2. Definitions
Now we give some definitions following ([3, 4, 5]).
: Number of partitions of n, like 4, 3+1, 2+2, 2+1+1, 1+1+1+1. Therefore,
and similarly
etc.
Crank of partitions [2]: For a partition
, let
denotes the largest part of
,
denote the number of 1’s in
, and
denote the number of parts of
larger than
, the crank
is given by;
: The number of partitions of n with crank m.
2.1. NotationsFor all integers
and all integers m, the number of n with crank equal to m is
, like;
But we see that;
Since, the coefficient of x in the right hand side of the equation;
is
i.e.,
the exponent of z being the crank of partition.
Therefore, 
3. The Generating Function for 
The generating function for
is given by [2];
 | (1) |
We see that the exponent of z represents the crank of partitions of n (for
). As for examples when n = 5 and 6,
For n = 5,
For n = 6,
4. Vector Partitions of n
Let,
, where D denotes the set of partitions into distinct parts and P denotes the set of partitions. The set of vector partitions V is defined by the Cartesian product,
.
For
, where
weight =
, the crank
.
We have 41 vector partitions of 4 are given in the following table:
From the above table we have,
and


1–1= 0



i.e.,
=
i.e., 
Again we have 83 vector partitions of 5 are given in the following table:
From this table we have;

1–1–1–1–1+1+1+1+1+1+1+1–1–1–1 =1
1–1–1–1–1+1+1+1+1+1+1+1–1–1–1 =1
1+1–1–1–1–1+1+1+1–1= 0
1+1–1–1–1–1+1+1+1–1= 0
1+1–1–1+1= 1
1+1–1–1+1= 1
1–1= 0
1–1= 0
1
1
;
i.e.,
= 7
i.e.,
=
.
From above discussion we get;
Theorem: The number of partitions
of n with crank
is
for all
.
Proof: The generating function for
is given by;
 | (2) |
Now we distribute the function into two parts where first one represents the crank with
and second one represents the crank with
.
The first function is;
Counts (for
) the number of partitions with no 1’s and the exponent on z being the largest part of the partition where
, like;
Here n = 4, the 5th term is
.
Again second partition is,
which counts the number of partitions with
and the exponent on z is clearly
, since
, like;
Here n = 4, the 5th term is
i.e.,
.
Thus in the double series expansion of
, we see that the coefficient of
is the number of partitions of n in which
. Equating the coefficient of
from both sides in (2) we get the number of partitions of n with
is
for all
. Hence the Theorem.
5. Conclusion
We have verified that the coefficient of x in the right hand side of the generating function for
is an explanation of z, the exponents of z represent the crank of partitions, it is already shown with examples for n = 5 and 6. We have satisfied the result
=
, it is already shown when n = 4 and 5 respectively. For any positive integer of n we can verify the corresponding Theorem. We have already satisfied the Theorem for n = 4 and 5.
Acknowledgment
It is a great pleasure to express our sincerest gratitude to our respected Professor Md. Fazlee Hossain, Department of Mathematics, University of Chittagong, Bangladesh. We will remain ever grateful to our respected Late Professor Dr. Jamal Nazrul Islam, RCMPS, University of Chittagong, Bangladesh.
References
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| In article | |
|
[2] | Andrews, G.E. and Garvan, F.G., Dyson’s Crank of a Partition, Bulletin (New series) of the American Mathematical Society, 18(2): 167-171. 1988. |
| In article | |
|
[3] | Atkin, A.O.L. and Swinnerton-Dyer, P., Some Properties of Partitions, Proc. London Math. Soc. 3(4): 84-106. 1954. |
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|
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| In article | |
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[5] | Garvan, F.G.. Dyson’s Rank Function and Andrews’ spt-function, University of Florida, Seminar Paper Presented in the University of Newcastle on 20 August 2013. 2013. |
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|