Scholz conjecture
Encyclopedia
In mathematics
, the Scholz conjecture sometimes called the Scholz–Brauer conjecture or the Brauer–Scholz conjecture (named after A. Scholz and Alfred T. Brauer), is a conjecture
from 1937 stating that
As an example, l(5) = 3 (since 1 + 1 = 2, 2 + 2 = 4, 4 + 1 = 5, and there is no shorter chain) and l(31) = 7 (since 1 + 1 = 2, 2 + 1 = 3, 3 + 3 = 6, 6 + 6 = 12, 12 + 12 = 24, 24 + 6 = 30, 30 + 1 = 31, and there is no shorter chain), so
Brauer proved that
where l* is the length of the shortest star chain (an addition chain where every element of the chain is the sum of its predecessor and some other element). For many values of n,and in particular for n ≤ 2500, they are equal: l(n) = l*(n). But Hansen showed that there are some values of n for which l(n) ≠ l*(n), such as n = 26106 + 23048 + 22032 + 22016 + 1 which has l*(n) = 6110, l(n) ≤ 6109.
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
, the Scholz conjecture sometimes called the Scholz–Brauer conjecture or the Brauer–Scholz conjecture (named after A. Scholz and Alfred T. Brauer), is a conjecture
Conjecture
A conjecture is a proposition that is unproven but is thought to be true and has not been disproven. Karl Popper pioneered the use of the term "conjecture" in scientific philosophy. Conjecture is contrasted by hypothesis , which is a testable statement based on accepted grounds...
from 1937 stating that
- l(2n − 1) ≤ n − 1 + l(n) where l(n) is the length of the shortest addition chainAddition chainIn mathematics, an addition chain for computing a positive integer n can be given by a sequence of natural numbers v and a sequence of index pairs w such that each term in v is the sum of two previous terms, the indices of those terms being specified by w:Often only v is given since it is easy to...
producing n. N. Clift checked this by computer for n ≤ 46.
As an example, l(5) = 3 (since 1 + 1 = 2, 2 + 2 = 4, 4 + 1 = 5, and there is no shorter chain) and l(31) = 7 (since 1 + 1 = 2, 2 + 1 = 3, 3 + 3 = 6, 6 + 6 = 12, 12 + 12 = 24, 24 + 6 = 30, 30 + 1 = 31, and there is no shorter chain), so
- l(25−1) = 5 − 1 + l(5).
Brauer proved that
- l*(2n−1) ≤ n − 1 + l*(n)
where l* is the length of the shortest star chain (an addition chain where every element of the chain is the sum of its predecessor and some other element). For many values of n,and in particular for n ≤ 2500, they are equal: l(n) = l*(n). But Hansen showed that there are some values of n for which l(n) ≠ l*(n), such as n = 26106 + 23048 + 22032 + 22016 + 1 which has l*(n) = 6110, l(n) ≤ 6109.