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Algorithm to make strictly magic tesseracts

1. Algorithm for orders divisible by 8

   A strictly magic tesseract (namely, a 2,3,4-agonal magic tesseracts) can exist for orders divisible by 8. In this case, an associated strictly magic tesseract can exist. If the order is divisible by 16, there exists a Nasik magic tesseract, which satisfies a stronger condition than strictly magic. It is unknown what condition is required and sufficient for the existence of strictly magic tesseracts.

1.1 Associated strictly magic tesseracts (m = 8x)

An associated strictly magic tesseract aijkh of order m, where i,j,k,h = 0,...,m-1, is given by the following equation:
aijk = Tm(bijkh) m3 + Tm(cijkh) m2 + Tm(dijkh) m + Tm(eijkh) + 1,

where
bijkh = Tm(i) + (m/4)Tm(j) + (m/4)Tm(k) + (m/4)Tm(h)   (mod. m),   0 <= bijkh < m,
cijkh = (m/4)Tm(i) + Tm(j) + (m/4)Tm(k) + (m/4)Tm(h)   (mod. m),   0 <= cijkh < m,
dijkh = (m/4)Tm(i) + (m/4)Tm(j) + Tm(k) + (m/4)Tm(h)   (mod. m),   0 <= dijkh < m,
eijkh = (m/4)Tm(i) + (m/4)Tm(j) + (m/4)Tm(k) + Tm(h)   (mod. m),   0 <= eijkh < m,
Tm(x) = x (where x < m/2), 3m/2-1-x (otherwise)    (identical to the definition of Tm(x) for pantriagonal magic cubes).

Note A strictly magic tesseract also exists for order 8x+4 higher than 8. Here is an example for order 12.

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2. Algorithms for odd orders

Updated!

   A strictly magic tesseract of odd order can exist if the order is higher than 14, and an associated strictly magic tesseract of odd order can exist under the same condition.
   Let L13 be lcm{y| y is odd and 3 <= y <= 13} = 32x5x7x11x13, where lcm means the least common multiple, and gcd means the greatest common divisor.

Note It is unknown whether a strictly magic tesseract exists for order 7, 9, 11, or 13. For order 3 and 5, a strictly magic tesseract cannot exist.

2.1 Case m = 2x+1, m >= 15, and gcd(m, L13) = 1 (associated, pan-2,3-agonal)

In this case, m is prime to 3, 5, 7, 11, and 13.
A strictly magic tesseract aijkh of order m, where i,j,k,h = 0,...,m-1, is given by the following equation (aijkh is also pan-2,3-agonal):
aijkh = bijkh m3 + cijkh m2 + dijkh m + eijkh + 1,

where
bijkh = 2i + 4j + k + 7h + (m+13)/2   (mod. m),   0 <= bijkh < m,
cijkh = 2i - 4j + k + 7h + (m+5)/2   (mod. m),   0 <= cijkh < m,
dijkh = 2i + 4j - k + 7h + (m+11)/2   (mod. m),   0 <= dijkh < m,
eijkh = 2i + 4j + 7k - h + (m+11)/2   (mod. m),   0 <= eijkh < m.

This tesseract is expressed as follows by the XmlHypercube format by Aale de Winkel:
   LP({2,4,1,7}+(m+13)/2,{2,-4,1,7}+(m+5)/2,{2,4,-1,7}+(m+11)/2,{2,4,7,-1}+(m+11)/2)

The value of the determinant
| 2 4 1 7|
| 2 -4 1 7|
| 2 4 -1 7|
| 2 4 7 -1|
equals to -256 = -28, which is prime to any odd integer, so this set of the formulae always generates a normal magic tesseract.

2.2 Case m = 2x+1, m >= 15, and 1 < gcd(m, L13) < m (associated, pan-2,3-agonal)

Let q be gcd(m, L13) and p be m/q. In this case, p > 1 and q > 1.
A strictly magic tesseract aijkh of order m, where i,j,k,h = 0,...,m-1, is given by the following equation (aijkh is also pan-2,3-agonal):
aijkh = Sm,q(bijkh) m3 + Sm,q(cijkh) m2 + Sm,q(dijkh) m + Sm,q(eijkh) + 1,

where
bijkh = 2i + 4j + k + 7h + (m+13)/2   (mod. m),   0 <= bijkh < m,
cijkh = 2i - 4j + k + 7h + (m+5)/2   (mod. m),   0 <= cijkh < m,
dijkh = 2i + 4j - k + 7h + (m+11)/2   (mod. m),   0 <= dijkh < m,
eijkh = 2i + 4j + 7k - h + (m+11)/2   (mod. m),   0 <= eijkh < m.
Sm(x) = Qp,q([x/q], x mod q),

where [x] means the integer part of x.

Qp,q(x, y), where 0 <= x < p and 0 <= y < q, is given by the following equations (identical to Qp,q(x, y) for Nasik magic cubes):
Qp,q(x, y) = qx + y (if 0 < x < p-1 and x is even),
qx + (q-1-y) (if 0 < x < p-1 and x is odd),
y/2 + (q-1)/2 (if x = 0 and y is even),
(y-1)/2 (if x = 0 and y is odd),
y/2 + (p-1)q (if x = p-1 and y is even),
(y-1)/2 + pq - (q-1)/2 (if x = p-1 and y is odd).

See the page for Nasik cubes to see examples of Qp,q(x, y) and Sm,q(x).

2.3 Case m = 2x+1, m >= 15, and gcd(m, L13) = m (associated)

In this case, m is a divisor of L13 = 32x5x7x11x13.
A strictly magic tesseract aijkh of order m, where i,j,k,h = 0,...,m-1, is given by the following equation (aijkh is also pan-2,3-agonal):
aijkh = S*m(bijkh) m3 + S*m(cijkh) m2 + S*m(dijkh) m + S*m(eijkh) + 1,

where
bijkh = 2i + 4j + k + 7h + (m+13)/2   (mod. m),   0 <= bijkh < m,
cijkh = 2i - 4j + k + 7h + (m+5)/2   (mod. m),   0 <= cijkh < m,
dijkh = 2i + 4j - k + 7h + (m+11)/2   (mod. m),   0 <= dijkh < m,
eijkh = 2i + 4j + 7k - h + (m+11)/2   (mod. m),   0 <= eijkh < m.

S*m(x) is defined as follows:
S*m(x) = Rq,m/q(x mod q, x mod (m/q)) - 1,

where q is the greatest prime factor of m (q is equal to 5, 7, 11, or 13).
Rq,m/q is an associated magic rectangle of order-(q,m/q). See the page for magic rectangles.

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This page was last updated on June 21, 2009.
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