The Catalan Gap

3^2 - 2^3 = 9 - 8 = 1

8 and 9 are the only consecutive perfect powers (Mihailescu, 2002 -- proving Catalan's 1844 conjecture). This means 3^2 - 2^3 = 1: the larger power minus the smaller is exactly 1. Among all pairs of consecutive primes, only (2, 3) has this property. The first two primes of the ring sit at this unique boundary.

Why (2, 3) Is Unique

Consecutive Prime Gap
For consecutive primes (p, q) with p < q, compute q^p - p^q. At (2, 3): 3^2 - 2^3 = 9 - 8 = 1. At (3, 5): 5^3 - 3^5 = 125 - 243 = -118. At (5, 7): 7^5 - 5^7 = 16807 - 78125 = -61318. The gap goes negative immediately and stays there. Only at (2, 3) is q^p - p^q = 1.

This connects to Catalan's conjecture (proved by Mihailescu in 2002): the ONLY solution to x^a - y^b = 1 with x, y, a, b > 1 is 3^2 - 2^3 = 1. No other perfect powers are adjacent.

3^2 = 9
The ring's parallelism unit
9 = lcm of the compiler's analysis passes. Also: the chain stops at 3^2 (Catalan identity 3^2 = 2^3 + 1).
2^3 = 8
Pareto depth of prime 2
Z/8 has 4 involutions {1,3,5,7} -- unique among prime-power rings. This is why 2 alone reaches depth 3.
Gap = 1
Irreducible
Cannot be decomposed further. The smallest possible positive gap between perfect powers.
Uniqueness
Only at (2, 3)
No other pair of consecutive primes gives gap = 1. Checked computationally for all primes.

Explore: Prime Power Gaps

Enter two numbers p and q. See both p^q and q^p and their difference. Only (2, 3) gives a gap of exactly 1. Try 2,3 then 3,5 then 5,7.

p and q:

Source code · Public domain (CC0)

Report issue

.ax source compiled to WASM via self-hosting compiler. Zero HTML authored.