请输入您要查询的百科知识：

　

词条 Sicherman dice
释义

  1. Mathematics

  2. History

  3. Mathematical justification

  4. References

  5. See also

  6. External links

Sicherman dice {{IPAc-en|ˈ|s|ɪ|k|ər|m|ən}} are the only pair of 6-sided dice that are not normal dice, bear only positive integers, and have the same probability distribution for the sum as normal dice.

The faces on the dice are numbered 1, 2, 2, 3, 3, 4 and 1, 3, 4, 5, 6, 8.

Mathematics

A standard exercise in elementary combinatorics is to calculate the number of ways of rolling any given value with a pair of fair six-sided dice (by taking the sum of the two rolls). The table shows the number of such ways of rolling a given value :

n23456789101112
# of ways12345654321

Crazy dice is a mathematical exercise in elementary combinatorics, involving a re-labeling of the faces of a pair of six-sided dice to reproduce the same frequency of sums as the standard labeling. The Sicherman dice are crazy dice that are re-labeled with only positive integers. (If the integers need not be positive, to get the same probability distribution, the number on each face of one die can be decreased by k and that of the other die increased by k, for any natural number k, giving infinite solutions.)

The table below lists all possible totals of dice rolls with standard dice and Sicherman dice. One Sicherman die is coloured for clarity: 1–2–2–3–3–4, and the other is all black, 1–3–4–5–6–8.

23456789101112
Standard dice1+11+2
2+1		1+3
2+2
3+1		1+4
2+3
3+2
4+1		1+5
2+4
3+3
4+2
5+1		1+6
2+5
3+4
4+3
5+2
6+1		2+6
3+5
4+4
5+3
6+2		3+6
4+5
5+4
6+3		4+6
5+5
6+4		5+6
6+5		6+6
Sicherman dice 1+1 2+1
2+1		 3+1
3+1
1+3		 1+4
2+3
2+3
4+1		 1+5
2+4
2+4
3+3
3+3		 1+6
2+5
2+5
3+4
3+4
4+3		 2+6
2+6
3+5
3+5
4+4		 1+8
3+6
3+6
4+5		 2+8
2+8
4+6
 3+8
3+8		 4+8

History

The Sicherman dice were discovered by George Sicherman of Buffalo, New York and were originally reported by Martin Gardner in a 1978 article in Scientific American.

The numbers can be arranged so that all pairs of numbers on opposing sides sum to equal numbers, 5 for the first and 9 for the second.

Later, in a letter to Sicherman, Gardner mentioned that a magician he knew had anticipated Sicherman's discovery. For generalizations of the Sicherman dice to more than two dice and noncubical dice, see Broline (1979), Gallian and Rusin (1979), Brunson and Swift (1997/1998), and Fowler and Swift (1999).

Mathematical justification

Let a canonical n-sided die be an n-hedron whose faces are marked with the integers [1,n] such that the probability of throwing each number is 1/n. Consider the canonical cubical (six-sided) die. The generating function for the throws of such a die is . The product of this polynomial with itself yields the generating function for the throws of a pair of dice: . From the theory of cyclotomic polynomials, we know that

where d ranges over the divisors of n and is the d-th cyclotomic polynomial. We note also that

.

We therefore derive the generating function of a single n-sided canonical die as being

and is canceled. Thus the factorization of the generating function of a six-sided canonical die is

The generating function for the throws of two dice is the product of two copies of each of these factors. How can we partition them to form two legal dice whose spots are not arranged traditionally? Here legal means that the coefficients are non-negative and sum to six, so that each die has six sides and every face has at least one spot. (That is, the generating function of each die must be a polynomial p(x) with positive coefficients, and with p(0) = 0 and p(1) = 6.)

Only one such partition exists:

and

This gives us the distribution of spots on the faces of a pair of Sicherman dice as being {1,2,2,3,3,4} and {1,3,4,5,6,8}, as above.

This technique can be extended for dice with an arbitrary number of sides.

References

  • {{citation

| doi = 10.2307/2689786
| last = Broline
| first = D.
| title = Renumbering of the faces of dice
| journal = Mathematics Magazine
| volume = 52
| issue = 5
| year = 1979
| pages = 312–315
| jstor = 2689786
| publisher = Mathematics Magazine, Vol. 52, No. 5}}
  • {{citation

| last1 = Brunson
| first1 = B. W.
| last2 = Swift
| first2 = Randall J.
| title = Equally likely sums
| journal = Mathematical Spectrum
| volume = 30
| issue = 2
| year = 1998
| pages = 34–36}}
  • {{citation

| last1 = Fowler
| first1 = Brian C.
| last2 = Swift
| first2 = Randall J.
| title = Relabeling dice
| journal = College Mathematics Journal
| volume = 30
| issue = 3
| year = 1999
| pages = 204–208
| jstor = 2687599
| doi = 10.2307/2687599
| publisher = The College Mathematics Journal, Vol. 30, No. 3}}
  • {{citation

| last1 = Gallian
| first1 = J. A.
| last2 = Rusin
| first2 = D. J.
| title = Cyclotomic polynomials and nonstandard dice
| journal = Discrete Mathematics
| volume = 27
| year = 1979
| pages = 245–259
| doi = 10.1016/0012-365X(79)90161-4
| mr = 0541471
| issue = 3}}
  • {{citation

| last = Gardner
| first = Martin
| authorlink = Martin Gardner
| title = Mathematical Games
| journal = Scientific American
| year = 1978
| volume = 238
| issue = 2
| pages = 19–32
| doi = 10.1038/scientificamerican0278-19}}

See also

  • Two-cube calendar

External links

  • Grand Illusion's Informational Page
  • Mathworld's Information Page
{{PlanetMath attribution|id=6738|title=Crazy dice}}

2 : Dice|Combinatorics
随便看

　

开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。

　

Copyright © 2023 OENC.NET All Rights Reserved
京ICP备2021023879号 更新时间：2024/11/11 8:54:02