2. Results
We consider binary strings
containing symbols
, which are our basis AT
objects[
2], with
zeros and
ones, having a fixed length
. We consider strings to be
messages transmitted through a communication channel between a source and a receiver, similarly to the Claude Shannon approach used in the derivation of information entropy [
28], and consider the process of their formation within the AT framework.
Definition 1.
A string assembly index is the smallest number of steps s required to assemble a binary string of length N by joining two basic symbols contained in the initial assembly pool and strings joined in previous steps that are added to the assembly pool. Therefore, the assembly index is a function of the string .
For example, the 8-bit string
can be assembled in at most seven steps:
- 1.
join 0 with 0 to form , adding to P,
- 2.
join with 1 to form , adding to P,
- 3.
...
- 7.
join with 1 to form ,
six or five steps:
join 0 with 0 to form , adding to P,
join with 1 to form , adding to P,
join with taken from P to form , adding to P,
join with 0 to form , adding to P,
join with 1 to form ,
or at least four steps:
join 0 with 1 to form , adding to P,
join with 0 to form , adding to P,
join with taken from P to form , adding to P,
join with taken from P to form ,
which also ensures that the assembly pool
P is a distinct set. Therefore, the string (
1) has an assembly index
that represents the length of its shortest assembly pathway;
cannot be assembled in fewer steps.
Definition 2.
A string is a balanced string if it has the same number of symbols, where or if N is odd.
Without loss of generality, we assume that if N is odd, (e.g., for , , and ). However, our results are equivalently applicable if we assume the opposite (i.e. a larger number of ones for an odd N).
The number
of balanced strings among all
strings is
1
This is OEIS A001405 sequence, the maximal number of subsets of an N-set such that no one contains another, as asserted by Sperner’s theorem, and approximated using Stirling’s approximation for large N.
BBs emit Hawking black-body radiation having a continuous spectrum that depends only on one factor, the BB temperature
corresponding to the BB diameter
, where
and
is the Planck length and temperature [
8].
Triangulated BB surfaces contain a balanced number of Planck area triangles, each having binary potential
, where
c denotes speed of light in vacuum, as has been shown [
8,
10], based on the Bekenstein-Hawking entropy [
29,
30,
31]
. Here
is the Boltzmann constant and
is the information capacity of the BB surface, i.e., the
Planck triangles corresponding to bits of information [
8,
9,
10,
30,
32,
33], and the fractional part triangle(s) having the area
too small to carry a single bit of information [
8,
9].
Therefore, a balanced string
represents a BB surface comprising
active Planck triangles (APTs) with binary potential equal to
[
9].
Theorem 1. A string having length is the shortest string having more than one string assembly index 1.
Proof.
The proof is trivial. For
the assembly index
, as all basis
objects have a pathway assembly index of 0 [
2] (they are not
assembled).
provides four available strings with
.
provides eight available strings with
. Only
provides 16 strings that include four stings with
and twelve strings with
including
balanced strings, as shown in
Table 1 and
Table 2.
For example, to assemble the string we need to assemble the string and reuse it. Therefore, for and for , where denotes a set of different assembly indices. □
Interestingly, Theorem 1 strengthens the meaning of
as the minimum information capacity that provides a minimum thermodynamic (BH) entropy [
29,
30,
31].
There is no disorder or uncertainty in an object that can be assembled in the same number of steps .
Conjecture 1 (Tight lower bound on the string assembly index). The smallest string assembly index as a function of N corresponds to the shortest addition chain for N (OEIS sequence A003313).
Partial Proof.
Strings for which , can be formed by joining two basic symbols, adding the pair to the pool and joining the longest strings taken from the pool until N is reached. This sets the bound for , where s is the number of assembly steps and . Only four strings , , , and have such an assembly index in this case. □
Theorem 2 The length of an elegant binary program required to assemble a string that has the smallest assembly index is equal to its assembly index.
Proof.
An elegant program is the shortest program that produces a given output [
34,
35]. The assembly pool
P is a distinct set, to which strings are added in subsequent assembly steps. Thus, we can define
-
Command 0: Take the last two elements from P, join them with each other, and output.
-
and
-
Command 1: Take the last element from P, join it with itself, and output.
as the only two commands of a binary program F of length applicable to the initial assembly pool containing only two basic symbols.
The bit of the program F is irrelevant as assembles and assembles and we can denote it by . Then the programs assemble the -bit strings having the assembly index , while strings with the smallest assembly index can be assembled with the same two programs starting with the pool to .
The remaining
programs will assemble some of the shorter strings with the assembly index
. In general, all programs
F assemble strings having lengths expressible as a product of Fibonacci numbers (OEIS A065108) as shown in
Table A2, wherein out of
programs (cf.
Table 6)
programs assemble strings including the strings ,
programs assemble strings,
programs assemble strings,
⋯,
the program assembles the shortest string having length belonging to the set of Fibonacci numbers, and
the program assembles two such strings into a string of length being twice the Fibonacci sequence (OEIS A055389).
For , some of the programs are no longer elegant and some of the assembled strings do not have the minimal assembly index. For example, the program assembles the string , but if this string can be assembled by a shorter program , and if this string does not have the minimal assembly index but . For and for the shortest string assembled by the program F the program F is not elegant for and the shortest string it assembles is not for . However, the length of any program F is not shorter than the assembly index of the string which this program assembles. □
The assembly programs
F are listed in
Table 3,
Table 4 and
Table 5 for one version of the assembly pool and for
.
We note in passing that Theorem 2 would be violated if we defined the command "1" e.g. as "take the last element from the assembly pool, join it with itself, join with what you have already assembled (say at "the right"), and output". Then the 2-bit program "11" would produce
with the assembly index
. However, such a one-step command would violate the axioms of assembly theory since it would perform two assembly steps in one program step. An elegant program to output the gigabyte binary string of all zeros would take a few bits of code and would have a low Kolmogorov complexity [
36]. However, such a string would be
outputted, not
assembled. Furthermore, the length of such a program that outputs the string
would be shorter than the length of the program that outputs the string
, while in AT, the lengths of these programs must be the same. Theorem 2 is about
binputation2 of binary strings.
Table 6.
6-bit programs assembling strings with .
Table 6.
6-bit programs assembling strings with .
| F |
|
N |
|
|
21 |
|
|
26 |
|
|
|
|
|
|
|
|
|
|
|
|
Theorem 2 is related to Gödel’s incompleteness theorems and the halting problem.
N cases of the halting problem correspond only to
, not to
N bits of information [
37]. Therefore,
N-bit elegant programs assemble all four strings
with
(with two versions of the assembly pool). Furthermore, we can consider all strings assembled by the
N-bit assembly program as corresponding to provable theorems. Any formal axiomatic system only enables proving only true theorems [
38].There is a more fundamental path to incompleteness that involves complexity, rather than self-reference [
38].
In the following, we conjecture the form of the upper bound of the set of different string assembly indices 1.
In general, of all strings
having a given assembly index, shown in
Table 1 and
Table A3,
Table A4,
Table A5,
Table A6,
Table A7,
Table A8,
Table A9,
Table A10, most are those having
. The only exceptions are
for
(
) and for
(
),
for
(
) and for
(
), and
for
(
).
Introducing the definition 2 of a balanced string allows us to reduce the search space of possible strings with maximal assembly indices to balanced strings only. With the exception of , of all strings having a maximum assembly index, most are balanced.
We can further restrict the search space to distinct strings.
Definition 3.
A string is a distinct string if a ring formed with this string by joining its beginning with its end is unique among the rings formed from the other distinct strings .
There are at least two and at most
N forms of a distinct string
that differ in the position of the starting symbol. For example for
balanced strings, shown in
Table 2, two augmented strings with
correspond to each other if we change the starting symbol
Similarly, four augmented strings with
correspond to each other
after a change in the position of the starting symbol. Thus, there are only two distinct strings for
The number of distinct strings among all strings is given by the OEIS sequence A000031. In general (for ), the number of distinct strings is much lower than the number of balanced strings.
As asserted by the no-hair theorem [
39], BH is characterized only by three parameters: mass, electric charge, and angular momentum.
However, BHs are fundamentally uncharged and non-rotating, since the parameters of any conceivable BH, that is, charged (Reissner-Nordström), rotating (Kerr) and charged rotating (Kerr-Newman), can be arbitrarily altered, provided that the area of a BH surface does not decrease [
40] using Penrose processes [
41,
42] to extract electrostatic and/or rotational energy of a BH [
43].
Thus, a BH is defined by a single real number, and no Planck triangle is distinct on a BH surface. We can define neither a beginning nor an end of a balanced distinct string that represents a given BH.
By neglecting the notion of the beginning and end of a string, we focus on its length and content. In Yoda’s language,
"complete, no matter where it begins. A message is".
The numbers of the balanced
, distinct
, and balanced distinct
3 strings are shown in
Table 7 and
Figure 1.
We note that, in general, the starting symbol is relevant for the assembly index. Thus, different forms of a distinct string may have different assembly indices. For example, for
balanced strings
and
, shown in
Table A13 have
. However, these strings are not distinct, since they correspond to each other and to the balanced strings
,
,
,
, and
with
. They all have the same triplet of adjoining ones.
Definition 4.
The assembly index of a distinct string is the smallest assembly index among all forms of this string.
Thus, if different forms of a distinct string have different assembly indices, we assign the smallest assembly index to this string. In other words, we assume that the smallest number of steps
where
denotes a particular form of a distinct string
, is the string assembly index of this distinct string.
If an object that can be represented by a distinct string (a BB in particular) can be assembled in fewer steps, this procedure will be preferred by nature.
The distribution of the assembly indices of the balanced distinct strings
is shown in
Table 8.
If a string for which is constructed from repeating patterns, then a string for which must be the most patternless. The string assembly index must be bounded from above and must be a monotonically nondecreasing function of N that can increase at most by one between N and .
Identifying the shortest pathway is known to be computationally challenging [
3]. This problem has been proven to be at least as hard as NP-complete [
44]. However, certain heuristic rules apply in our binary case. For example,
for we cannot avoid two doublets (e.g. ) within a distinct string and thus ,
for we cannot avoid two pairs of doublets (e.g. and ) within a distinct string and thus ,
for we cannot avoid three pairs of doublets (e.g. , , and ) within a distinct string and thus ,
for we cannot avoid two pairs of doublets and one doublet three times (e.g. , , and , and thus ,
etc.
Conjecture 2.
The problem of determining the assembly index of a given binary string is NP-complete [44], while the problem of creating the string so that it would have a predetermined maximum assembly index for this length of the string is NP-hard.
We found it much easier to determine an assembly index of a given binary string than to create a string so that it would have a maximum assembly index as a function of the length of the string. A proof of conjecture 2 would also be the proof of the following conjecture.
Every computable problem and every computable solution can be encoded as a finite binary string. Here, determining whether the assembly index of a given string has its known maximal value corresponds to checking the solution to a problem for correctness, whereas creating such a string corresponds to solving the problem. Thus, AT would solve the P versus NP problem in theoretical computer science. There is ample pragmatic justification for adding
as a new axiom [
37].
Table 9 shows the exemplary balanced strings
having maximal assembly indices that we created (cf. also
Appendix B). To determine the assembly index
of the string
we look for the longest patterns that appear at least twice within the string, and we look for the largest number of these patterns. Here, we find that each of the two triplets
and
appear twice in
and are based on the doublets
and
also appearing in
. Thus, we start with the assembly pool
made in four steps and join the elements of the pool in the following seven steps to arrive at
. On the other hand, another form of this balanced distinct string
has
.
Conjecture 4 (Tight upper bound on a string assembly index). With exceptions for small N the largest string assembly index of a binary string as a function of N is given by a sequence formed by strings for , where denotes increasing by one, and 0 denotes maintaining it at the same level, and .
However, at this moment, we cannot state if this conjecture applies to distinct or non-distinct strings. The assembly indices for
are unique, whereas the assembly indices for
were discussed above and are calculated in
Appendix C for balanced and balanced distinct strings.
The conjectured sequence is shown in
Figure 2 and
Figure 3 starting with
(we note in passing that
is a dimension of the void, the empty set
∅, or (-1)-simplex). Subsequent terms are given by
, which is periodic for
and flattens at
, and
,
,
.
This sequence can be generated using the following procedure
We note the similarity of this bound to the Aufbau rule
4, the Janet sequence (OEIS A167268) and the monotonically non-decreasing Shannon entropy of chemical elements, including observable ones [
23]. Perhaps the exceptions in the sequence 4 vanish as
N increases.
The bounds 1 and 4 are shown in
Table 7 and illustrated in
Figure 2 and
Figure 3. No binary string cannot be assembled in a smaller number of steps than given by a lower bound (cf. Conjecture 1). On the other hand, some strings cannot be assembled in a smaller number of steps than given by an upper bound (which for large
N, as we suppose, has the form presented in Conjecture 4).
Conjecture 5.
There is no binary program that has a length shorter than the length of the string featuring the largest assembly index that could assemble this string.
Partial Proof.
In assembling the string featuring the assembly index (the largest complexity), we cannot rely solely on the last or two last strings in the assembly pool. Thus, we need to index the strings in the pool. However, we cannot predict in advance how many strings there will be in the assembly pool. Thus, we do not know how many bits will be needed to encode the indices. □
The Hamlet tragedy contains approximately 130,000 letters. Assigning five bits per letter (32 possibilities), the Hamlet tragedy can be encoded in a string having
bits (81.25 kB) yielding the total number of possible strings
(including
), and their assembly indices are bounded by
The lower bound (
8) can be estimated using the Conjecture 1. The upper bound (
8) can be estimated by finding the smallest
k that satisfies
and using the relation
of Conjecture 4.
We assume that the assembly index of the string encoding the actual Hamlet tragedy is close to the upper bound. Even if the probability of random typing of the Hamlet tragedy is unfathomably small, when constrained to the bounds of the physical universe [
5], as asserted by the infinite monkey theorem, this tragedy was once created by William Shakespeare.
SARS-CoV-2 genome sequence contains 29903 bases
. Assigning two bits per base it can be encoded in a string of
bits having the assembly index bounded by
The supermassive BH Sagittarius A ∗ has an estimated mass
kg corresponding to the Schwarzschild diameter
m and the information capacity
[
8]. In this case, its assembly index is bounded by
However, we conjecture that
Conjecture 6.
A BB surface is defined by a balanced distinct string that satisfies the upper bound of a distinct string assembly index.
To be the most patternless [
8], a balanced BB surface must minimize not only Shannon entropy and Kolmogorov complexity (the latter is uncomputable), but also maximize its assembly index. A BB cannot be assembled in a suboptimal way, since black-body radiation is informationless.