• 沒有找到結果。

Three Dimensional Patterns Generation Problems

在文檔中 Pattern Generation Problems (頁 87-99)

en-tropy such as in3.4.2. Equation (3.4.55) implies h(Ax;2×2×2) > 0, if a diagonal periodic cycle applied, with a maximum eigenvalue in (3.4.55) larger than 1.

This method powerfully yields the positivity of spatial entropy, which is hard in examining the the complexity of patterns generation problems.

The rest of this paper is organized as follows. Section 3.2, we derive a recursive formula to obtain the ordering matrix Ax;2×m2×2 for Σ2×m2×2 from Ax;2×2×2. Convert the ordering [x] into [ˆx]. Then, construct the similar recur-sive formula for ordering matrix Axˆ;2×m2×m3 from Axˆ;2×m2×2. Section3.3 we derives the recursive formula for the associated higher order transition ma-trices Txˆ;2×m2×m3 from Tx;2×2×2. Section 3.4 derives the connecting operator Cm which can recursively reduce higher elementary patterns to patterns of lower order. Then, the lower-bound of spatial entropy can be found by com-puting the maximum eigenvalues of the diagonal periodic cycles of sequence Sˆx;m3;m1m.

§ 3.2 Three Dimensional Patterns Generation Problems

This section describes three dimensional patterns generation. Let S be a set of p colors, Zm1×m2×m3 be a fixed finite rectangular sublattice of Z3, where Z3 denotes the integer lattice on R3 and (m1, m2, m3) a 3-tuple of positive integers. Functions U : Z3 → S and Um1×m2×m3 : Zm1×m2×m3 → S are called global patterns and local patterns on Zm1×m2×m3 respectively. The set of all patterns U is denoted by ΣP ≡ SZ3, i.e., Σp is the set of all patterns with p different colors in 3-dimensional lattice. For clarity, we begin by studying two symbols, i.e., S = {0, 1}. There are three coordinates, let x-, y- and z-coordinate represent the 1st-, 2ed- and 3rd-coordinate respectively. There are six orderings [O] ordering could be represented as follows:

[x] : [1] ≻ [2] ≻ [3], [y] : [2] ≻ [1] ≻ [3], [z] : [3] ≻ [1] ≻ [2], [ˆx] : [1] ≻ [3] ≻ [2], [ˆy] : [2] ≻ [3] ≻ [1], [ˆz] : [3] ≻ [2] ≻ [1].

(3.2.1)

On a fixed finite lattice Zm1×m2×m3, we firstly give an ordering [O] = Om1×m2×m3

on Zm1×m2×m3 which belongs to any one of above orderings on Zm1×m2×m3

by [O] : [i] ≻ [j] ≻ [k]

O(α1, α2, α3) = mjmki− 1) + mkj − 1) + αk. (3.2.2)

84 Pattern Generation Problems

By identifying the pictorial patterns by numbers O(U), it becomes highly ef-fective in proving theorems since computations can now be performed on O(U). For example, the orderings on Z2×2×2could be represented as follows:

[x]-ordering [ˆx]-ordering

3.2. THREE DIMENSIONAL PATTERNS GENERATION PROBLEMS85 where α1 means the α1-th layer in x-coordinate. As denoted by the 1 × m2× m3 pattern

ax;1×m2×m3;iα1 =

uα11m3 uα12m3 · · · uα1m2m3

... ... . .. ...

uα112 uα122 · · · uα1m22

uα111 uα121 · · · uα1m21 (3.2.6) .

In particular, when m2 = 2 and m3 = 2 as denoted by ax;1×2×2;iα1, where iα1 = 1 + 23uα111+ 22uα112+ 2uα121+ uα122

(3.2.7) and

ax;1×2×2;iα1 = uα112 uα122

uα111 uα121

.

A 2 × 2 × 2 pattern U = (uα1α2α3) can now be obtained by [x]-direct sum of two 1 × 2 × 2 patterns using [x]-ordering, i.e.,

ax;2×2×2;i1i2 = ax;1×2×2;i1 ⊕ ax;1×2×2;i2

= (3.2.8) ,

where iα1 as in (3.2.7) and α1 ∈ {1, 2}. Therefore, the complete set of 28 patterns in Σ2×2×2 can be listed by a 16 × 16 matrix Ax;2×2×2 = [ax;2×2×2;i1i2] as its entries in

where .

(3.2.9)

It is easy to verify that

x(ax;2×2×2;i1i2) = 24(i1− 1) + i2, (3.2.10)

86 Pattern Generation Problems i.e., we are counting local patterns in Σ2×2×2 by going through each row successively in (3.2.9). Correspondingly, Ax;2×2×2 can be referred to as an ordering matrix for Σ2×2×2. A 2×2×2 pattern can also be viewed as [x]-direct sum of two 1 × 2 × 2 patterns using [ˆx]-ordering, i.e.,

axˆ;2×2×2; ˆi1iˆ2 = ax; ˆˆi1 ⊕ ax; ˆˆi2

(3.2.11) where

α1 = 1 + 23uα111+ 22uα121+ 2uα112+ uα122, α1 ∈ {1, 2}, (3.2.12)

such as in (3.2.5). And the ordering matrix Axˆ;2×2×2 can be represented as

where .

(3.2.13)

It could be verified that ˆ

x(ax; ˆˆi1iˆ2) = 24( ˆi1− 1) + ˆi2. (3.2.14)

Similarly, a 2 × 2 × 2 pattern can also be viewed as a [y]-direct ([ˆy]-direct) and [z]-direct ([ˆz]-direct) sum of 2 × 1 × 2 and 2 × 2 × 1 pattern, i.e.,

ay;j1j2 = ay;j1 ⊕ ay;j2, ay; ˆˆj1jˆ2 = ay; ˆˆj1 ⊕ ay; ˆˆj2, az;k1k2 = az;k1 ⊕ az;k2, aˆz; ˆk1kˆ2 = az; ˆˆk1 ⊕ az; ˆˆk2, where

jα2 = 1 + 23u21+ 22u22+ 2u21 + u22, α2 ∈ {1, 2}, (3.2.15)

α2 = 1 + 23u21+ 22u21+ 2u22 + u22, α2 ∈ {1, 2}, (3.2.16)

kα3 = 1 + 23u11α3 + 22u12α3 + 2u21α3 + u22α3, α3 ∈ {1, 2}, (3.2.17)

α3 = 1 + 23u11α3 + 22u21α3 + 2u12α3 + u22α3, α3 ∈ {1, 2}.

(3.2.18)

3.2. THREE DIMENSIONAL PATTERNS GENERATION PROBLEMS87 A 16 × 16 matrix Ay;2×2×2 = [ay;2×2×2;j1j2] or Az;2×2×2 = [az;2×2×2;k1k2] can also be obtained for Σ2×2×2, i.e., we have Ay;2×2×2 =

where ,

(3.2.19)

or Az;2×2×2

where .

(3.2.20)

The relations between Aω;2×2×2must be explored, where ω ∈ {x, y, z, ˆx, ˆy, ˆz}.

Before explaining the relations we denote column matrix and row matrix. Let A= [aij] be a m2× m2 matrix, the column matrix A(c) of A is defined by

A(c) = 





A(c)1 A(c)2 · · · A(c)m2

A(c)m2+1 A(c)m2+2 · · · A(c)2m2

... ... . .. ...

A(c)(m2−1)m2+1 A(c)(m2−1)m2+2 · · · A(c)m4





, (3.2.21)

A(c)alpha = 





a a · · · am2α

a(m2+1)α a(m2+2)α · · · a(2m2

... ... . .. ...

a((m2−1)m2+1)α a((m2−1)m2+2)α · · · am4α



, (3.2.22)

88 Pattern Generation Problems where1 ≤ α ≤ m4.

And the row matrix A(r) of A is defined by A(r) = 





A(r)1 A(r)2 · · · A(r)m2

A(r)m2+1 A(r)m2+2 · · · A(r)2m2

... ... . .. ...

A(r)(m2−1)m2+1 A(r)(m2−1)m2+2 · · · A(r)m4





, (3.2.23)

A(r)α = 





aα1 aα2 · · · aαm2

aα(m2+1) aα(m2+2) · · · aα(2m2)

... ... . .. ...

aα((m2−1)m2+1) aα((m2−1)m2+2) · · · aαm4



, (3.2.24)

where 1 ≤ α ≤ m4. Therefore, from some observations, Ax;2×2×2 can be represented by ay;j1j2 as

Ax;2×2×2 = A(r)y;2×2×2. (3.2.25)

The remainder of this subsection is devoted to construct Axˆ;2×m2×m3 from Ax;2×2×2 by the following three steps, where Axˆ;2×m2×m3 represented the or-dering matrix of Σ2×m2×m3 according to [ˆx]-ordering generated from Σ2×2×2.

Step I : Use [x]-ordering on Z1×m2×2 by

2m2-2 2

2m2-3 2m2-1

y

(3.2.26)

and introduce ordering matrix Ax;2×m2×2 for Σ2×m2×2.

Step II : Convert [x]-ordering into [ˆx]-ordering on Z1×m2×2 by

2 2 2

(3.2.27)

and introduce ordering matrix Axˆ;2×m2×2 for Σ2×m2×2.

3.2. THREE DIMENSIONAL PATTERNS GENERATION PROBLEMS89 Step III : Define [ˆx]-ordering on Z1×m2×m3 by

(m3-1)m2+1 (m3-1)m2+2 3 2

(3.2.28) z

and introduce ordering matrix Axˆ;2×m2×m3 for Σ2×m2×m3. To introduce Ax;2×m2×2, define

ay;2×m2×2;j1j2...j2m2 = ay;2×2×2;j1j2⊕aˆ y;2×2×2;j2j3⊕ · · · ˆˆ ⊕ay;2×2×2;jm2−1jm2

= ay;j1 ⊕ ay;j2⊕ · · · ⊕ ay;jm2, (3.2.29)

where 1 ≤ jk ≤ 24 and 1 ≤ k ≤ m2. Herein, a wedge direct sum ˆ⊕ is used for 2 × 2 × 2 patterns whenever they can attached together.

Now, Ax;2×m2×2 can be obtained as follows.

Theorem 3.1. For any m2 ≥ 2, Σ2×m2×2 = {ay;j1j2...jm2}, where ay;j1j2...j2m2 is given in (3.2.29). Furthermore, the ordering matrix Ax;2×m2×2 = [ay;j1j2...jm2] which is a 22m2 × 22m2 matrix can be decomposed into following matrices

Ax;2×m2×2 = [Ax;2×m2×2;j1]2m2×2m2,

where 1 ≤ j1 ≤ 22m2. For fixed j1, j2, . . . , jk∈ {1, 2, . . . , 22m2}, Ax;2×m2×2;j1j2...jk = [Ax;2×m2×2;j1j2...jkjk+1]m2×m2,

where 1 ≤ jk+1 ≤ 22m2 and k ∈ {1, 2, · · · , m2−2}. For fixed j1, j2,· · · , jm2−1, Ax;2×m2×2;j1j2...jm2−1 = [ay;2×m2×2;j1j2...jm2−1jm2]2m2×2m2,

where ay;2×m2×2;j1j2...jm2 is defined in (3.2.29).

Proof. From (3.2.15), uα1α2α3 can be solved in terms of jα2, i.e., we have u21 = [jα2 − 1

23 ], (3.2.30)

u22 = [jα2 − 1 − 23u21

22 ],

(3.2.31)

u21 = [jα2 − 1 − 23u21 − 22u22

2 ],

(3.2.32)

u22 = jα2 − 1 − 23u21− 22u22 − 2u21, (3.2.33)

90 Pattern Generation Problems where [ ] is the Gauss symbol. From (3.2.30) to (3.2.33), we have the following table.

jα2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

u21 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1

u22 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1

u21 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1

u22 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1

For any m2 ≥ 2, we have

im2;1 = 1 +

m2

X

α2=1

(22(m2−α2)+1u21+ 22(m2−α2)u22), (3.2.34)

im2;2 = 1 +

m2

X

α2=1

(22(m2−α2)+1u21+ 22(m2−α2)u22).

(3.2.35)

From above formulae, we have

im2+1;1 = 22(im2;1− 1) + 2u1(m2+1)1+ u1(m2+1)2+ 1, im2+1;2 = 22(im2;2− 1) + 2u2(m2+1)1 + u2(m2+1)2+ 1.

Now, by induction on m2 the theorem follows from last two formulae and the above table. The proof is complete.

Remark 3.2. By the similar method, the following relations ca be derived but the detailed proof is omitted here for brevity.

Aˆx;2×2×m3 = [az;2×2×m3;k1k2...km3−1km3]2m3×2m3

(3.2.36)

Ay;m1×2×2 = [ax;m1×2×2;i1i2...im1−1im1]2m1×2m1

(3.2.37)

Ayˆ;2×2×m3 = [aˆz;2×2×m3;k1k2...km3−1km3]2m3×2m3

(3.2.38)

Az;m1×2×2 = [aˆx;m1×2×2;i1i2...im1−1im1]2m1×2m1

(3.2.39)

Azˆ;2×m2×2 = [ayˆ;2×m2×2;j1j2...jm2−1jm2]2m2×2m2

(3.2.40)

Next, [x]-ordering is converted into [ˆx]-ordering for Z1×m2×2. Since Z1×m2×2 = {(1, α2, α3) : 1 ≤ α2 ≤ m2,1 ≤ α3 ≤ 2}, the position (α2, α3) is the α-th in (3.2.26), where

α= 2(α2− 1) + α3. (3.2.41)

In (3.2.27), the position of (1, α2, α3) is the ˆα-th, where ˆ

α= m23− 1) + α2. (3.2.42)

3.2. THREE DIMENSIONAL PATTERNS GENERATION PROBLEMS91 It is easy to verify

ˆ

α= m2α+ (1 − 2m2)[α− 1

2 ] + (1 − m2), (3.2.43)

or

ˆ

α= k if α= 2k − 1, and

ˆ

α= m2 + k if α = 2k, 1 ≤ k ≤ m2.

Now, the ordering [ˆx] in (3.2.27) on Z1×m2×2 can be extended to Z1×m2×m3 by (3.2.28). For a fixed m2, [ˆx]-ordering on Z1×m2×m3 is clearly one di-mensional; it grows in z-direction. With ordering (3.2.28) on Z1×m2×m3, for U = (uα1α2α3) ∈ Σ2×m2×m3, denoted by

ˆiα1 = 1 +

m2

X

α2=1 m3

X

α3=1

uα1α2α32m2(m3−α3)+(m2−α2), (3.2.44)

where α1 = 1, 2. Then, we obtain ˆ

x(U) = 2m2m3( ˆi1− 1) + ˆi2. (3.2.45)

Now, let ax; ˆˆi1iˆ2 = U = (uα1α2α3), then we have new ordering matrix Axˆ;2×m2×2 = [axˆ;2×m2×2; ˆi1iˆ2] for Σ2×m2×2. The relationship between Ax;2×m2×2and Axˆ;2×m2×2

is established before constructing Aˆx;2×m2×m3 from Aˆx;2×m2×2 for m3 ≥ 3.

We firstly established a conversion sequence of orderings from (3.2.26) to (3.2.27). Where Pk denotes the permutation of N2m = {1, 2, · · · , 2m2} such that Pk(k + 1) = k,Pk(k) = k + 1 and the other numbers are fixed. We also denote Pk the permutation on Z1×m2×2 such that it exchanges k and k+1 and maintains the other positions fixed, i.e,

· k+ 1 · ·

· · k ·

Pk

−→ · k · ·

· · k+ 1 ·

(3.2.46)

Obviously (3.2.26) can be converted into (3.2.27) in many ways by using sequence of Pk. Here, we present a systematic approach.

Lemma 3.3. For m2 ≥ 2, (3.2.26) can be converted into (3.2.27) by the following sequences of m2(m22−1) permutations successively

(P2P4· · · P2m2−2)(P3P5· · · P2m2−3) · · · (PkPk+2· · · P2m2−k) · · · (Pm2−1Pm2+1)Pm2, (3.2.47)

2 ≤ k ≤ m2.

92 Pattern Generation Problems Proof. When m2 = 2 and 3, verifying that (3.2.47) can convert (3.2.26) into (3.2.27) is relatively easy.

When m2 ≥ 4, and for any 2 ≤ k ≤ m2, applying

(P2P4· · · P2m2−2)(P3P5· · · P2m2−3) · · · (PkPk+2· · · P2m2−k) (3.2.48)

to (3.2.26), then there are two intermediate cases:

(i) when 2 ≤ k ≤ [m22], then we have

1 2 · · · k k+ 2 k+ 4 · · · k+ 2ℓ · · · · · · 2m2− 3k + 1 · · · 2m2− k − 22m2− k k+ 1 k+ 3 · · · 3k − 1 · · · · · · · · · 3k − 1 + 2ℓ · · · 2m2− k − 12m2− k + 1 · · · 2m2− 1 2m2

(3.2.49)

where 0 ≤ ℓ ≤ m2− 2k.

(ii) when [m22] + 1 ≤ k ≤ m2− 1, then we have

· · ·

· · ·

· · ·

· · ·

· · ·

· · ·

· · ·

· · ·

1 2 k− 1 k k+ 2 2m2− k

k+ 1 2m2− k − 12m2− k + 12m2− k + 2 2m2− 1 2m2

(3.2.50)

When k = m2 in (3.2.50), we have (3.2.27). We prove (3.2.49) and (3.2.50) by mathematical induction on k. When k=2, it is relatively easy to verify that (3.2.26) is converted into

· · ·

· · ·

· · ·

· · ·

· · ·

· · ·

1 2 4 2m2− 12m2− 2

3 5 2m2− 32m2− 1 2m2

by P2P4· · · P2m2−2, i.e., (3.2.49) holds for k=2. Next, assume that (3.2.49) holds for k ≤ [m2]. Then, by applying Pk+1Pk+2· · · P2m2−k−1to (3.2.49), it can be verified that (3.2.49) holds for k + 1 when k + 1 ≤ [m22] or becomes (3.2.50) when k + 1 ≥ [m22]. When k ≥ [m22] + 1, we apply Pk+1Pk+3· · · P2m2−k−1 to (3.2.50). It can also be verified that (3.2.50) holds for k+1. Finally, we conclude that (4.27) holds for k = m2. The proof is thus complete.

By using Lemma 3.3, Ax;2×m2×2 can be converted into Axˆ;2×m2×2 by the following construction. Let

P =



1 0 0 0 0 0 1 0 0 1 0 0 0 0 0 1



, (3.2.51)

3.2. THREE DIMENSIONAL PATTERNS GENERATION PROBLEMS93 and for 2 ≤ j ≤ 2m2− 2, as denoted by

Px;2m2;j = I2j−1 ⊗ P ⊗ I22m2−j−1, (3.2.52)

where Ik is the k × k identity matrix. Furthermore, let Px;2×m2×2 = (P2m2;2P2m2;4· · · P2m2;2m2−2)

· · · (P2m2;k· · · P2m2;2m2−k) · · · (P2m2;m2), (3.2.53)

2 ≤ k ≤ m2. Then, we have the following theorem.

Theorem 3.4. For any m2 ≥ 2,

Axˆ;2×m2×2 = Ptx;2×m2×2Ax;2×m2×2Px;2×m2×2. (3.2.54)

Proof. From (3.2.41), in Z1×m2×2 the position (α2, α3) is the α-th in (3.2.26), where α = 2(α2− 1) + α3. Define

α = 1 + 2u2α3 + u2α3, (3.2.55)

1 ≤ ℓα ≤ 4 and 1 ≤ α ≤ 2m2. For U = (uα1α2α3) ∈ Σ2×m2×2, from Theorem 3.1 it can be denoted by ay;2×m2×2;j1j2...jm2 and by (3.2.15) for fixed 1 ≤ α2 ≤ m2 we have

jα2 = 1 + 23u21+ 22u22+ 2u21+ u22

= 22(ℓ2−1) + ℓ2 + 1,

where 1 ≤ jα2≤16. Hence the relation between ay;jα2 and wy;ℓ2α2−12α2 is



ay;1 ay;2 ay;3 ay;4

ay;5 ay;6 ay;7 ay;8 ay;9 ay;10 ay;11 ay;12 ay;13 ay;14 ay;15 ay;16



 =



w11 w12 w21 w22

w13 w14 w23 w24 w31 w32 w41 w42 w33 w34 w43 w44



.

Therefore, the pattern in ordering matrix Ax;2×m2×2 can be represented by ay;2×m2×2;j1j2...jm2 = ay;j1 ⊕ ay;j2 ⊕ · · · ⊕ ay;jm2

= wy;ℓ12 ⊕ wy;ℓ34 ⊕ · · · ⊕ wy;ℓ2m2−12m2

≡ wy;ℓ12...ℓ2m2. It is easy to verify that for any 1 ≤ k ≤ 2m2− 1,

P2mt 2;kAx;2×m2×2P2m2;k

= P2mt 2;k[wy;ℓ12...ℓkk+1...ℓ2m2]P2m2;k

= [wy;ℓ12...ℓk+1k...ℓ2m2],

i.e., P2m2;k exchanges ℓk and ℓk+1 in Ax;2×m2×2. Therefore, from (3.2.53) and Lemma 3.3, (3.2.54) follows.

94 Pattern Generation Problems Now, in Theorem 3.4, as denoted by

Axˆ;2×m2×2 = [axˆ;2×m2×2; ˆi1iˆ2], (3.2.56)

1 ≤ ˆi1,ˆi2 ≤ 2m2. And by Remark 3.2, Aˆx;2×m2×2 could be represented by az;2×m2×2;k1k2, where 1 ≤ k1, k2 ≤ 22m2. The [ˆx]-expression

Axˆ;2×m2×2 = A(r)z;2×m2×2 (3.2.57)

for Σ2×m2×2 enable us to construct Aˆx;2×m2×m3 for Σ2×m2×m3. Indeed, for fixed m2 ≥ 2 and m3 ≥ 2, let

axˆ;2×m2×m3; ˆi1iˆ2 = az;2×m2×m3;k1k2...km3

= az;2×m2×2;k1k2⊕aˆ z;2×m2×2;k2k3⊕ · · · ˆˆ ⊕az;2×m2×2;km3−1km3. (3.2.58)

Therefore, by a similar argument as in proving Theorem 3.1 we have the following theorem for Axˆ;2×m2×m3. The detailed proof is omitted here for brevity.

Theorem 3.5. By fixing m2 ≥ 2 and for any m3 ≥ 2, the ordering matrix Aˆx;2×m2×m3 with respect to [ˆx]-ordering can be expressed as

Axˆ;2×m2×m3 = [Axˆ;2×m2×m3;k1]2m2×2m2, (3.2.59)

where 1 ≤ k1 ≤ 22m2. For fixed 1 ≤ k1, k2,· · · , kl ≤ 22m2, Axˆ;2×m2×m3;k1k2···kl = [Axˆ;2×m2×m3;k1k2···klkl+1]2m2×2m2

(3.2.60)

where 1 ≤ kl+1 ≤ 22m2 and 1 ≤ l ≤ m3− 2. For fixed k1, k2,· · · , km3−1, Aˆx;2×m2×m3;k1k2···km3−1 = [az;2×m2×m3;k1k2...km3],

(3.2.61)

where az;2×m2×m3;k1k2...km3 is given by (3.2.58).

Remark 3.6. Similarly, the following relations can be derived but the de-tailed proof is omitted here for brevity.

Ax;2×m2×m3 = [ay;2×m2×m3;j1j2...jm2]2m2m3×2m2m3

Ay;mˆ 1×2×m3 = [az;mˆ 1×2×m3;k1k2...km3]2m1m3×2m1m3

Ay;m1×2×m3 = [ax;m1×2×m3;i1i2...im1]2m1m3×2m1m3

Az;mˆ 1×m2×2 = [ay;mˆ 1×m2×2;j1j2...jm2]2m1m2×2m1m2

Az;m1×m2×2 = [ax;mˆ 1×m2×2;i1i2...im1]2m1m2×2m1m2

在文檔中 Pattern Generation Problems (頁 87-99)

相關文件