Commonalities of Kolmogorov Topologic Spaces and Addition Chains

A table of values m(n) with n ≤ 5086 follows:
n12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364
+00 122334344545554556566656666767566767776777777867777878788878886
+6477878887888888978888889898989997888898989998999899999998999999107
+12888989998999999108999999109991091010108999999109109109101010910101091010109101010101010118
+19299991091091010109101010910101010101010910101010101011910101010101010101010111011101191010101010101110101011101111108
+2569910910101091010101010101191010101010101110101011101111119101010101010111010101110111111101110111011111110111111111111119
+3201010101010101110111011101111111011111110111111101111111111111110111111111111111011111111111111101111111111111111111112111111119
+38410101010111011101111111011111110111111111111111011111111111111101111111111111111111112111111121011111111111112111111121112121110
+4481111111111111111111111111211121112111211121212111212121112121210111111111111121111111211121211111211121112121211121212121211129
+51210101110111111101111111111111210111111111111121111111211121212101111111111111211111112111212121111111211121212111212121212121210
+57611111111111112111111121112121211121112111212121112121212121212111212121112121211121212121212121112121212121212121212131212121210
+64011111111111112111211121112121211121212111212121112121212121212111212121212121211121212121212121112121212121212121212121212121211
+70412121212121212121212121212121311121212121212131212121212131212111212121212121312121212121212121213121312131312121312131212121310
+76811111111121112111212121112121211121212121212121112121212121213111212121212121212121213121212121112121212121213121212131213121211
+83212121212121212121212121212121312121213121313131213121312131313111212121212121312121213121313121213121312131313121313121313121311
+89612121212121212121212131213121312131213121312131213131312131313121313131213131312131313131313131213131313131313121313131313131311
+96012121212121213121212131213131212131213121313131213131313131213121313131213131312131313131313131213131313131313131313131213131310
+102411111211121212111212121212121311121212121212131212121312131313111212121212121312121213121313131212121312131313121313131313131311
+108812121212121213121212131213131312121213121313131213131313131313121312131213131312131313131313131213131313131313131313131313131311
+115212121212121213121212131213131312131213121313131213131313131313121313131213131312131313131313131213131313131313131313131313131312
+121613131313131313121313131313131312131313131313131313131313131313121313131313131313131313131313131313131413131313131313131313131411
+128012121212121213121312131213131312131313121313131213131313131313121313131313131312131313131313131213131313131313131313141313131312
+134413131313131313131313131313131312131313131313141313131313141313121313131313131413131313131313131313131413141313131413131313131412
+140813131313131313131313131313131413131314131413141314131413141414121313131313131413131314131414131314131413141314131314131314131412
+147213131313131314131313141313131313141314131413131314131413141314131414141314141413141414141413141314141413141414131413141314141411
+153612121212131213121313131213131312131313131313131213131313131314121313131313131313131314131313141213131313131314131313141314141312
+160013131313131313131313131313131313131314131414141313131413141314121313131313131413131314131414131313131413141414131414131314131412
+166413131313131313131313141313131413131313131413141314131413141414131413141314141413141414141414141314141413141414131414141414141412
+172813131313131314131313141314141313141314131414141314141314141314131414141314141413141414141414141314141414141314141414141314141412
+179213131313131313131313141314131413141314131414141314141413141414131414141314141413141414131414141314141414141414131414141414141413
+185614141414141414131414141414141413141414141414141414141414141414131414141414141414141414141414141314141414141414141414141414141412
+192013131313131314131313141314141313141314131414141314141414141314131414141314141413141414141414141314141414141414141414141314141413
+198414141414141414131414141414141413141414141414141414141414141414131414141414141414141414141414141414141414141414131414141414141511
+204812121312131313121313131313131412131313131313141313131413141414121313131313131413131314131414141313131413141414131414141414141412
+211213131313131314131313141314141413131314131414141314141414141414131313141314141413141414141414141314141414141414141414141414141412
+217613131313131314131313141314141413131314131414141314141414141414131413141314141413141414141414141314141414141414141414141414141413
+224014141413141414131414141414141413141414141414141414141414141414131414141414141414141414141414141414141414141414141414141414141512
+230413131313131314131313141314141413141314131414141314141414141414131414141314141413141414141414141314141414141414141414141414141413
+236814141414141414131414141414141413141414141414141414141414141414131414141414141414141414141414141414141514141414141414141414141513
+243214141414141414141414141414141413141414141414141414141514141414131414141414141514141414141414141414141514151414141414141414141513
+249614141414141414141414141414141414141415141414141415141414151415141414151414151414151415141414151415141414151415141514151415151512
+256013131313131314131413141314141413141414131414141314141414141415131414141414141413141414141414141314141414141414141414141414141413
+262414141414141414141414141414141413141414141414141414141414151414131414141414141514141414141414141414141514151514141514141414141513
+268814141414141414141414141414141414141414141414151414141414151415131414141414141514141415141515141414141414151415141415141415141513
+275214141414141415141414151414141414141414141514141415141414151415141514151415151514151514141514151415151514141415141514151415151513
+281614141414141414141414141414141514141415141514151415141514151515141514151415151514151515141515151415151514151515141515151515151513
+288014141414141415141414151415151414151415141515151414151415151415141515151415151514151515141415151415141515151415141515151415151513
+294414141414141415141414151414141414151415141515141415141514151415141515151415151514151515141514151415151514151515141515151415151514
+300815151515151515141515151515151514151515151515151515151514151515141515151515151514151515151515151415151514151515141515151515151512
+307213131313141314131414141314141413141414141414141314141414141415131414141414141414141415141414151314141414141415141414151415151413
+313614141414141414141414141414141514141415141515151414141514151515131414141414141514141415141515141414141514151515141515141515141513
+320014141414141414141414151414141414141414141514151414141514151415141414151415151514151515151515151415141514151515141515151415151513
+326414141414141415141414151415151414141415141515151415151415151415141514151415151514151515151515151415151415151415141515151415151513
+332814141414141414141414151414141514141415141515151415141514151515141514151415141514151515141515151415151514151515141515151515151514
+339215151514151515141515151515151514151515151515151515151515151515141515151515151514151515151515151415151515151515151515151515151513
+345614141414141415141414151415151414151415141515151415151415151415141515151415151514151515151515151415151515151415151515151415151514
+352015151515151515141515151515151514151515151515151515151515151515141515151515151515151515141515151515151515151515141515151515151613
+358414141414141414141414151415141514151415141515151415151514151515141515151415151514151515151515151415151515151515141515151515151514
+364815151515151515141515151515151514151515151515151415151515151515141515151515151515151515151515151415151515151515151515151515151514
+371215151515151515151515151515151514151515151515151515151515151515141515151515151515151515151515151515151515151515151515151515151614
+377615151515151515151515151515151515151515151515151515151515151515141515151515151515151515151615151515151515151515151515151516151613
+384014141414141415141414151415151414151415141515151415151515151415141515151415151514151515151515151415151515151515151515151415151514
+390415151515151515141515151515151514151515151515151515151515151515141515151515151515151515151515151515151515151515141515151515151614
+396815151515151515151515151515151514151515151515151515151515151515141515151515151515151515151515151515151515151515151515151515151614
+403215151515151515151515151515151515151515151515151515151515161516151515151516151515161515151515161415151515151516151515161516161512
+409613131413141414131414141414141513141414141414151414141514151515131414141414141514141415141515151414141514151515141515151515151513
+416014141414141415141414151415151514141415141515151415151515151515141414151415151514151515151515151415151515151515151515151515151513
+422414141414141415141414151415151514141415141515151415151515151515141414151415151514151515151515151415151515151515151515151515151514
+428815141514151515141515151515151514151515151515151515151515151515141515151515151515151515151515151515151515151515151515151515151613
+435214141414141415141414151415151514141415141515151415151515151515141514151415151514151515151515151415151515151515151515151515151514
+441615151514151515141515151515151514151515151515151515151515151515141515151515151515151515151515151515151515151515151515151515151614
+448015151515151515141515151515151514151515151515151515151515151515141515151515151515151515151515151515151615151515151515151515151614
+454415151515151515151515151515151515151516151515151515151615151516151515151515151515151515151515161516151615161516151615161516161613
+460814141414141415141414151415151514151415141515151415151515151515141515151415151514151515151515151415151515151515151515151515151514
+467215151515151515141515151515151514151515151515151515151515151515141515151515151515151515151515151515151615151515151515151515151614
+473615151515151515151515151515151514151515151515151515151515151515141515151515151615151515151515151515151515161515151515151515151614
+480015151515151515151515151515151515151515151515151515151515161516151515161515161515161515151515161516151515151516151615161516161614
+486415151515151515151515151515151515151515151515151515151615161516141515151515151615151516151615151515151615151616151515151516151614
+49281515151515151615151516151515151515151515161515151515151516151615161516151616 15151615151515161515151615151516151615161516161614
+499215151515151515151515161515151515151516151515151516151515161516151615161516161515161516151615161516161515161516151516161516161615
+5056161516151616161516151616161516151616161516161615161516151616
Table entries with orange background color mean, that the corresponding ℓ(n) is 1 larger. This data can be obtained by computing all T(k,n) for k ≤ 15. The entries with value 16 can be deduced by the above mentioned inequalities m(n+2), m(n+1) ≤ m(n)+1, and m(n*h) ≤ m(n)+m(h).
All T(k,n) with k ≤ 11, were already calculated by M. Erné and K. Stege in 1990. To generate all posets with with 9,10,11,...,15 points, I used the poset package nauty version 2.4 from Gunnar Brinkmann and Brendan McKay.
In case you like to download the m(n)-values for further research as ascii-file (each line contains a triple n, m(n), ℓ(n)-m(n)).

Define t(k) = | {n ∈ N : m(n)=k } |, i.e. to be the number of sizes (their number of open sets) of finite topologies needing at least k points and define f(k) = min {n ∈ N : m(n)=k } , i.e. to be the minimal size (their number of open sets) of a finite topology needing at least k points. Remarkably it holds five times f(k)=2*f(k-1)-3, namely k ∈ { 4, 5, 6, 12, 14} and five times is f(k)+1 a power of two. namely k ∈ { 0, 2, 4, 10, 15}.
It follows a table to compare these sequences with the corresponding sequences c(k) and d(k) for shortest addition chains:
k c(k) s(c(k))f(k)d(k) t(k)
0 1 0 1 1 1
1 2 0 2 1 1
2 3 1 3 2 2
3 5 1 5 3 3
4 7 2 7 5 5
5 11 2 11 9 9
6 19 2 19 15 15
7 29 3 29 26 26
8 47 3 47 44 45
9 71 3 79 78 80
10 127 4127 136141
11 191 4191 246256
12 379 4379 432455
13 607 4635 772822
141087 4126713821499
151903 5204724812746
163583 535834490
We have |{n ∈ N: k=m(n)=ℓ(n)-1}| = ∑i ≤ k t(i)-d(i) for all k ≤ 15.

Lastly here are the numbers T(3,n), T(4,n), T(5,n), T(6,n), T(7,n), T(8,n), T(9,n), T(10,n), T(11,n), T(12,n), T(13,n), T(14,n) and T(15,n) if they are positive as plain ascii text files.


Achim Flammenkamp
Last update: 2020-06-02 17:45:18 UTC+1