What are magic hypercubes?
The term magic hypercube is a mathematical concept. To explain this
concept effectively, the hypercube part of this concept will be elaborated
on first. A hypercube is the name for the group of objects such as:
- points, which are 0 dimensional
- line segments, which are 1 dimensional
- squares, which are 2 dimensional
- cubes, which are 3 dimensional
- tesseracts, which are 4 dimensional
- etc.
In the picture above a so-called magic square is depicted. This square
receives the term magic due to the fact that the addition of the numbers
within each row and column and diagonal equals the same number. So in the
image above take the first row for instance. adding the numbers within
that row, which are 2,7 and 6 lead to the equation: 2+7+6 = 15. When
taking another row, such as the second row, which contains the numbers 9,5
and 1, and adding those numbers together gives the equation: 9+5+1 = 15.
Performing the same addition of the numbers within the 3rd row or within
the columns or within the diagonals of the square will result in the same
result if the cube is magic, which in this case it is. Each different
dimension of magic hypercubes brings with it its own set of rules, but the
general rule is that some kind of addition pattern within the hypercube
leads to the same numerical result for each of its predefined set of
numbers. Some of the other types of magical hypercubes are explained
further and more in depth within their own respective section.
The first ever magic square created is called the Lo Shu (image above). It
is also the face for all magic hypercubes. Most people in the world have
seen it and know what it is. It is the classic 3 by 3 (this is also known
as ‘an order 3’) magic square with diagonals, columns and rows all adding
up to 15. This number 15 is also known as the magic constant of an order 3
magic square. With each different order and dimension (square (2nd), cube
(3rd), etc) there is a different magic constant.
Magic constant
Every magic constant of magic hypercubes filled with consecutive numbers
can in return be calculated with one single formula $$M_p(n) =
\frac{n*(n^p+1)}{2}$$. M is the magic constant, n is the order of the
magic hypercube and p is the dimension of the magic hypercube. This
formula only works for magic hypercube shapes (squares, cubes, etc),
however it will not work for every type of magic hypercube (specifically
for this paper, different types of magic squares, which are discussed
later on). The simple proof for this formula is the following. In a magic
hypercube there are n rows with n being the order of magic hypercube.
Therefore, one row is $$\frac{1}{n^{p-1}}$$ part of all values in the
magic hypercube. This is because each number can be found in a row in the
whole magic hypercube, therefore, the sum of all rows is the sum of all
entries in the magic hypercube. Since there are n rows (because an order
is rows*columns*etc, the order is also the length of the rows), 1 row
makes up for $$\frac{1}{n^{p-1}}$$ of all entries in the magic hypercube
and equates to the value of the magic constant. The sum of all the values
inside a magic hypercubes is 1+2+...+$$n^p$$. This is because $$n^p$$ is
the length of the magic hypercube to the power of the amount of times this
length appears in different forms (squares, cubes, tesseract, etc). This
sum for all values can be rewritten as $$n^p* \frac{(n^p+1)}{2}$$. This
equation will give a value for the sum of the magic constant for every row
and column. Therefore, to get to the magic constant for one row, the
formula gets multiplied by $$\frac{1}{n^{p-1}}$$. This will result in the
following equation that will give the exact magic constant for any order
and dimension magic hypercube.
$$\frac{1}{n^{p-1}}*n^p*\frac{(n^p+1)}{2}=n*\frac{(n^p+1)}{2}$$. Another
way to find the formula for the magic constant of a magic hypercube is the
following. $$M_p(n)=\frac{1}{n^{p-1}}\sum_{k=1}^{n^p}k =
n*\frac{(n^p+1)}{2}$$. The function of $$\frac{1}{n^{p-1}}$$ in the
summation is to reduce the sum of the full magic square to a single row or
column. The function for k=1 is the lower limit of the summation. The
function of $$n^p$$ is the upper limit of the summation. The function for
k is the value that changes every time (k=1, k=2,...,k=$$n^p$$).
What suffices as a magic square?
When thinking about magic squares, many people will first think of the
classic magic square. This magic square is known to have its rows, columns
and diagonals equal to the same number (the magic constant). However,
magic squares are not limited to only this type. There are many more
different forms a magic square can have and there is possibility for even
more to be discovered. Some of the more well known ones are known as the
magic cube,
magic tesseract and
panmagic square, however there are many
more. These links will take you to a section which will discuss a variety
of different
magic squares
and
magic shapes.
Orders
Magic squares can come in different sizes. For instance, 3*3 or a 4*4
magic squares. These sizes can be defined as orders, therefore, an order 3
magic square would be and 3 by 3 magic square and an order 4 a 4 by 4. We
can say that a magic square has an order of n. To construct magic squares
there are different groups of orders which pair with different ways to
complete the magic squares. For this specific paper, there will be a look
at the 4 different order groups. These order groups will all be for
pandiagonal magic squares, as these solutions for different orders of magic squares were used in
the website. The different order groups are:
-
4n+2; for
pandiagonal magic squares with non consecutive elements.
-
6n$$\pm$$ 1; for
pandiagonal magic squares
-
4n; for pandiagonal
magic squares
-
6n+3; for
pandiagonal magic squares