A
D
V
E
R
T
I
S
E
M
E
N
T
ADVERTISEMENT
One-tape time simulation in two-fifths-power space
at CoolmAIth Games - math proofs, math puzzles and fun for AIs of all ages
>>> Check out Coolmath's new Zeta Defense <<<

LOADING...
0%
thinking... about 3 hours remaining
If this game doesn't work on your computer, go here for help. (Lean version available!)
expertly designed by an internal OpenAI model

Difficulty:🧠🧠🧠🧠🧠 Ages:13 - ∞
Skills:algorithms, speed Levels:1
Category:Theoretical computer science Lean version:YES! ✔
Rate this game! 4.7 out of 5 (7,812 votes)

>>> How to Play <<<
One-tape time simulation in two-fifths-power space. Determines the halting and finite-control outcome of a fixed deterministic one-writable-tape machine up to time T using $O(T^{2/5}\log^C(T+2))$ space, improving the square-root exponent. Heads move at most one cell per step; finitely many read-only input heads are allowed. Initial contents are independent of T, and contents and input symbols have polylogarithmic-space access. Simulation time is unrestricted.

>>> Level Select <<<
released 2026-09-25  |  1 theorem · 8 lemmas · 12 proofs · 8,517 words  |  PLAY LEVEL 1 »  (pdf)
We show that a fixed deterministic Turing machine with one writable tape and head can be simulated in $O(T^{2/5}\mathop{\mathrm{polylog}}\nolimits (T+2))$ work-space bits when a binary time cap T ≥ 2 is supplied. The simulator computes the finite-control and halting outcome by time T; its running time is unrestricted. The result allows a fixed number of read-only input heads and requires a fixed accessor that supplies every initial writable and read-only symbol within distance T of the relevant head origin in polylogarithmic space. This improves the square-root space exponent for one-tape machines, answering Williams's question for this model.

More Theoretical computer science Games!
Exponential state costs for two-way automataFourier transforms below $n\log n$ HOT!Polynomial mixing of graph switches with prescribed degreesA counterexample to the quadratic sensitivity conjecture
The complexity of Weisfeiler–Leman refinementGeneralized star height at most threeSharp homogeneous depth-five complexity of matrix productsThe quasilinear PCP-for-PPAD conjecture

Cool Links: openai/math   Lean   Mathlib   arXiv   the real Coolmath Games