Solution

Charlie S Delightful Machine Eric

First name
Eric
School
Dulwich College Beijing
Country
Age
12

Detailed Analysis of Multi-Bulb Lighting System with Cyclic On-Switching Pattern
1. System Description
The system here consists of four individual light bulbs—blue, red, yellow, and green—each programmed to turn on at specific independent times depending on an incremental "click" counter. Such a system is a discrete-time dynamical system where the state of each bulb (off or on) is computed using modulo arithmetic with respect to its lighting cycle. These systems serve as the foundation for the study of synchronization, periodicity, and combinatorial patterns in theoretical and real-life situations.
2. Individual Bulb Pattern of Activation
Every bulb possesses a deterministic pattern regarding its activation period. This is the rigorous analysis:
Blue Light Bulb
Cycle: 5 clicks
Mathematical Representation:
The blue bulb is activated when the number of clicks nn is one such that n≡0 (mod 5)n≡0 (mod 5).
Activation Sequence: 5, 10, 15, 20, 25…
Properties:
Maximum frequency of activation (shortest duration).
In NN click interval, it glows ⌊N5⌋⌊5N⌋ times.
Red Light Bulb
Cycle: 7 clicks
Mathematical Representation:
nn≡0 (mod 7)n changes in only 15 steps.
Activation Sequence: 7, 14, 21, 28, 35…
Properties:
A prime-numbered interval, which creates special synchronization properties.
Glows ⌊N7⌋⌊7N⌋ times in NN clicks.
Yellow Light Bulb
. Cycle: 9 clicks
. Mathematical Representation:
n≡0 (mod 9)n≡0 (mod 9).
Activation Sequence: 9, 18, 27, 36, 45…
Properties:
Composite interval (3²), with common factors for other intervals (18 with blue and green, for example).
Least frequent activation of the bulbs.
Green Light Bulb
Cycle: 8 clicks
Mathematical Representation:
n≡0 (mod 8)n≡0 (mod 8).
Activation Sequence: 8, 16, 24, 32, 40…
Properties:
Power-of-two interval (2³), supporting binary-like synchronization.
Switches on ⌊N8⌋⌊8N⌋ times.
3. Synchronization Analysis
Global behaviour of the system relies on interactions between these cycles. Key questions are:
When do subsets of bulbs light up together?
What is the minimum number of clicks to synchronize all bulbs?
Pairwise Synchronization
Blue (5) and Red (7):
LCM(5,7) = 35 clicks (first coordinated illumination at 35, 70…
Blue (5) and Green (8):
LCM(5,8) = 40 clicks.
Red (7) and Yellow (9):
LCM(7,9) = 63 clicks.
Full System Synchronization (All Bulbs)
Least Common Multiple (LCM) Calculation:
Prime factorizations:
5 = 5151,
7 = 7171,
8 = 2323,
9 = 3232.
LCM = 23×32×5×7=252023×32×5×7=2520 clicks.
Implications:
The system resynchronizes to a fully synchronized state after each 2520 clicks.
This increases exponentially with more bulbs or better cycles.
4. Statistical and Combinatorial Observations
Density of Activations:
Number of bulbs activated at click nn is combinatorial in nature. For example:
At n=30n=30: Blue (5, 10, 15, 20, 25, 30), Red (none), Yellow (9, 18, 27), Green (8, 16, 24).
Total lit up: Blue and Green.
Asymptotic Behaviour
For large NN, the expected number of bulbs turned on per click converges to:
15+17+19+18≈0.592
51+71+91+81≈0.592
5. Practical Applications
Traffic Light Coordination:
Cyclical patterns of the same duration maximize traffic passage through intersections.
Computer Science:
Real-time scheduling of tasks.
Polling algorithms in distributed environments.
Art and Design:
Light installations with changing dynamics based on synchronization gaps for visual effect.
6. Extensions and Open Problems
Variable Intervals:
How is synchronization if intervals are stochastic or time-variant?
Energy Efficiency:
Conserving power through optimization of concurrent activations.
Generalization to kk Bulbs
The LCM problem for generic cycles is computationally expensive.