Questions tagged [integer-partitions]

Use this tag for questions related to ways of writing a positive integer as a sum of positive integers.

In number theory and combinatorics, a partition of a positive integer $n$ is a way of writing $n$ as a sum of positive integers. Two sums that differ only in the order of their summands (also called parts) are considered the same partition. For example, all of the partitions of $4$ are $1 + 1 + 1 + 1$, $2 + 1 + 1$, $2 + 2$, $3 + 1$, or $4$.

The number of partitions of $n$ is given by the partition function $p(n)$. For the example above, $p(4) = 5$.

Partitions can be visualized graphically with Ferrers diagrams.

Partitions have applications in symmetric polynomials, the symmetric group, and group representations.

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Canonical partition function identity

The grand canonical partition function, Z, is given by $$ Z = \sum_{M=0}^\infty G(M)z^M =\frac{V_0(z)U_L(z)}{1−U(z)V (z)} \tag{1} $$ where G(M) is the canonical partition function of a chain of length M, z is the fugacity and $$ U(z) =…
Mark
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mesh of the partition $P = \{1,3,4,5\}$

Consider the interval $[1, 5]$ and the partition $P = \{1, 3, 4, 5\}$, what is the mesh of this partition? So i'd say the mesh of this is $\text{mesh}(P) = \max{(|P_{i} - P_{i - 1}|)}$ for $i = 1, ..., 4$. Now what do I do here? If we choose $P_{1}…
user2850514
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Partitions that have at most k parts and all parts <= j

Let p¯k(n) be the number of partitions of n with largest part at most k which is equivalent to partition into at most k parts. I do know an expression for that function. ( product of 1/1(1-n) through 1/(1-n)^k ) What I am searching for is an…
blues
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conjugate partition definition

i would like to understand basic definition of conjugate partition,this is what is said in my book Let $υ = (u_1, u_2, . . . , u_n)$ be a sequence of integers such that $u_1 ≥ u_2 ≥ · · · ≥ u_n ≥ 0.$ The conjugate partition of $υ$ is $υ∗ = (u_1^*,…
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Show that the number of $1$s in all the partitions equals the sum of number of distinct elements in each partition

Consider the number $n$ a partition $P$ of $n$. Denote by $f_n(P)$ the number of $1$s in $P$ and by $g_n(P)$ the number of distinct elements in $P$. Show that $\displaystyle\sum_{P} f_n(P) = \displaystyle\sum_{P} g_n(P)$. Note that a partition is a…
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Dilworth's Lemma

We want to place $2012$ pockets, including variously colored balls, into $k$ boxes such that either For all boxes, all pockets in a box must include a ball with the same color or For all boxes, all pockets in a box must include a ball…
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Schengen Visa rules

If a tourist wants to visit europe with a schengen visa, the following rules apply: maximum contiguous stay is 90 days (in the following treated as 3 months) in any 180 day interval the sum of days must not exceed 90 days. If somebody wants to…
user392629
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Restricted Integer Partitions

Two Integer Partition Problems Let $P(n,k,m)$ be the number of partitions of $n$ into $k$ parts with all parts $\leq m$. So $P(10,3,4) = 2$, i.e., (4,4,2); (4,3,3). I need help proving the following: $P(2n,3,n-1) = P(2n-3,3, n-2)$ $P(4n+3, 3, 2n+1)…
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What does George Andrews mean by i in "Theory of Partitions"?

From the first page of chapter 1 of George Andrews "Theory of Partitions" (Rather ominous place to get stuck): What do these last two sentences mean? I don't get "where exactly $f_l$ of the $\lambda_j$ are equal to $i$." Can one of you rephrase…
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All the different ways to add a set of lengths - need explanation of the answer

I wish to make an integer length n of boards laid down end to end. Each board is an integer length and among boards of one length there are unique types. For example, boards of length one come in two types: "1a", "1b" while boards of length two…
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Understanding about paper related to integer partition with even parts distinct

Let $ped(n)$ denote the number of partition of a positive integer $n$ wherein the even parts are distinct and the odd parts are unrestricted. I follow this paper: Andrews, G. E., Hirschhorn, M. D., & Sellers, J. A. (2010). Arithmetic properties of…
math404
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Non-standard partition of integers question

The question is as follows. Partition an integer $n$ into $r$ distintc parts with each part ranges from $[1,m]$ and the parts order is irrelevant. How many ways of different partitions are there? Note here it is different from the classic partition…
user85356
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The binary partition function $b(n)$ is even for all $n \ge 2$.

Let $b(n)$ be the binary partition function of $n$, i.e., the number of partition of $n$ for which all parts are the powers of two, and have properties $b(2n+1)=b(2n)$ and $b(2n)=b(n)+b(2n-2)$ for all positive integer $n$. Prove that $b(n) \equiv 0…
user1089451
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Error in Data Partitions with refinement property

I'm considering these data in my set: A B C D 1 a \$ F 1 A - T 2 A \$ D 2 A \$ F 2 b - L 3 b \$ O 3 C - F 3 C # R for each attribute A,B,C, and D it is possible to define the following data…
Stefano
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Euler's partition method. How does someone use it?

I came across partitions recently and am not very much informed about it but I have a question regarding Euler's method for this. I came to know about this formula from a YouTube video so, it may not be the full equation. Symbols: P(n) -> Partition…