Click here and add this page to your favorites!

|
Encyclopedia Britannica - Main :: I27-INV |
|
|
IIIIII, 2IIII, 221I, 222, 3111, 321, 33 , where no part is greater than 3; and so in general we have the theorem, the number of partitions of n into not more than k parts is equal to the number of partitions of n with no part greater than k. We have for the number of partitions an analytical theory depending on generating functions; thus for the partitions of a number n with the parts 1, 2, 3, 4, 5, &c., without repetitions, writing down the product I +x. r +x2. I +x3. I +x4 ... , = I +x+x2 -2X3... +Nx^+... , it is clear that, if xa, x13, xY, . are terms of the series x, x2, x3,for which a+3+y+ =n, then we have in the development of the product a term
term
function
function
Thus for the function 1 I x Ix2. -x3. . . =+x+2x2+.,+Nx"+,,,, observing that any factor 1/r x1 is=l+x1+x21+... , we see that in the term Nx" the coefficient is equal to the number of partitions of n, with the parts 1, 2, 3, . . , with repetitions. Introducing another letter z, and considering the functionI+xz.I+x2z.I+x3z. . .,=l+z(x+x2+. .)...+Nx"zk+, we see that in the term Nx"zk of the development the coefficient N is equal to the number of partitions of n into k parts, with the parts 1, 2, 3, 4, , without repetitions. And similarly, considering the function - xZ . I - I x3Z. .' =I+z(x+x2+..)...+Nx"zk+.. Ix22.- we see that in the term Nx"zk of the development the coefficient N is equal to the number of partitions of n into k parts, with the parts I, 2, 3, 4, , with repetitions. We have such analytical formulae as I-xZ.I-x22.I-x3Z. I +I , x+ rx I-x2+" which lead to theorems in the partition
I -x. I -x2. I -x3. I -x4. = I -x-x2+x5+x7-x12-x15+... , where the only terms are those with an exponent z (3n2 tn), and for each such pair of terms the coefficient is The formula
II, 821, 731, 641, 632, 542 10.1,92, 83, 74, 65, 5321, in each set 6. We have rx.1+x.I+x2.I+x4.1+x2... =1; or, as this may be written, 1+x. I +x2 . I +x4. I +x8... = I I x, = I +x+x2-{-x3+... , showing that a number n can always be made up, and in one way only, with the parts 1, 2, 4, 8, . The product on the left-hand side may be taken to k terms only, thus if k=4, we have 18 I +x.I +x2. I +x4.I +.',C8,= _ 1I x '=i+x+x2...+x15, number or of the successive numbers 1, 2, 3, &c. And of course in any case, having obtained the partitions, we can count them and so obtain the number of partitions.Another method is by L. F. A. Arbogast's rule
letter in each term, the rule
An important notion is that of conjugate partitions. zx 22x2 11 that is, any number from t to 15 eau be made up, and in one way only, with the parts 1, 2, 4, 8; and similarly any number from 1 to 2kI can be made up, and in one way only, with the parts 1, 2, 4, .. 2k-1. A like formula
Ix3 1x9 1x27 1x31 1x81 x.I x x3.Ix3 x9. Ix9 x27.Ix27 x40.Ix' that is, x'+I+x.x 3+I+x3.x-9+I+x9.x'7+I+x27 =x-40+x-39. +I+x ... +x39+x90, showing that any number from -40 to +40 can be made up, and that in one way only, with the parts 1, 3, 9, 27 taken positively or negatively; and so in general any number from -s(3k-I) to +(3k-1) can be made up. and that in one way only, with the parts t, 9, . . 3k-' taken positively or negatively. See further COMBINATORIAL ANALYSIS . (A. CA.)End of Article: IIIIII, 2IIII, 221I, 222, 3111, 321, 33 If you wish, you can link directly to this article.
<a href="http://jcsm.org/StudyCenter/Encyclopedia/I27_INV/IIIIII_2IIII_221I_222_3111_321.html"> IIIIII, 2IIII, 221I, 222, 3111, 321, 33 </a> |
|
|
(Previous) IIII |
(Next) IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIII... |
Jesus Christ Saves Ministries, P.O. Box 70696, Pasadena, CA 91117JCSM is a 501(c)(3), non-profit organization. Copyright © 1997-present. |
Free & Cheap Cell
Phones |
Cheap Long Distance
Phone Service Carriers |
Talk America Local Phone Service
|
Ztel & MCI - Unlimited Long Distance
Compare
Cell Phone Plans & Companies |
International Calling Cards & Prepaid Phone Cards |
Voice Over IP Broadband Internet Phone
Service | Wireless
Phone Plans & Cheap Cell Phones
|
_____________________________________________________________________________