The Septum

192 / 1001

Of every 1001 elements in Z/12,612,600, exactly 192 are units -- invertible, with all 6 CRT channels nonzero. The ratio 192/1001 = 19.18% comes from multiplying six Euler factors: (1-1/2)(1-1/3)(1-1/5)(1-1/7)(1-1/11)(1-1/13). One factor per prime. The other 80.82% are zero-divisors: at least one channel is zero, so they cannot be inverted.

The Derivation

An element n is a unit (invertible) if and only if gcd(n, N) = 1 -- it shares no prime factor with N. The count of such elements is Euler's totient:

Septum Theorem (PROVED)
phi(N)/N = (1-1/2)(1-1/3)(1-1/5)(1-1/7)(1-1/11)(1-1/13) = (1/2)(2/3)(4/5)(6/7)(10/11)(12/13) = 192/1001 = 19.18%. The ratio depends only on which primes divide N, not their exponents. phi(12,612,600) = 2,419,200 units. Z/970,200 (5 primes, no 13): 16/77 = 20.78%.

Numerator: 192 = 2^6 * 3. Denominator: 1001 = 7 * 11 * 13. The fraction of units is determined entirely by the six primes dividing the ring.

Units
2,419,200
phi(12,612,600). All 6 CRT channels nonzero.
Zero-divisors
10,193,400
N - phi(N). At least one channel is zero. 80.82%.
6-prime ratio
192/1001
= 2^6*3 / (7*11*13). Euler product of the six primes.
5-prime ratio
16/77
= 2^4 / (7*11). Without the mod-13 channel. 20.78%.

Projector Decomposition

The identity 1 splits into two orthogonal idempotent projectors:

1,576,576
CRT = (0, 1, 1, 1, 1, 1)
2^420 mod 12,612,600. Kills the mod-8 channel, preserves the other five. Idempotent: x^2 = x.
11,036,025
CRT = (1, 0, 0, 0, 0, 0)
The complementary projector. Preserves only the mod-8 channel.
Sum = 1
1,576,576 + 11,036,025 = 12,612,601 = 1 mod N
The two projectors add to the identity. Their product is 0. Orthogonal decomposition.

These are the two extremes of unit structure: the projector that kills one channel (mod-8) and the one that keeps only that channel. Together they partition the ring.

The Persistence Gradient

How long does each element survive before self-annihilating? The chain IS a persistence gradient:

ElementSteps to 0Bits/stepMeaning
1infinite-Never annihilates. 1^k = 1 forever.
23 steps1.0Most persistent prime. 2^3 = 0 mod 8.
32 steps1.583^2 = 0 mod 9.
52 steps2.325^2 = 0 mod 25.
72 steps2.817^2 = 0 mod 49. Deepest 2-step pool.
111 step3.4611 = 0 mod 11. Instant.
131 step3.7013 = 0 mod 13. Instant.
00 steps-Already zero.
Persistence Theorem (PROVED)
p^k -> 0 mod p^e takes exactly e steps. The Pareto exponents {3, 2, 2, 2, 1, 1} are the persistence depths. 2 is the most persistent prime (3 steps). 11 and 13 are the most volatile (1 step each).

Information drip rate: 2 leaks 1 bit/step (slowest), 7 leaks 2.81 bits/step (deepest 2-step pool), 11 leaks 3.46 bits in 1 step.

The Seventh Prime

Adding the seventh prime (17) extends the ring from Z/12,612,600 to Z/214,414,200. The unit fraction gains one more Euler factor: (16/17). Everything above remains true -- the six-prime foundation is unchanged. The seventh prime deepens it.

TRANS Septum (PROVED)
phi(214,414,200) / 214,414,200 = 3072/17017 = 18.05%. Seven Euler factors: (1/2)(2/3)(4/5)(6/7)(10/11)(12/13)(16/17). Numerator: 3072 = 2^10 * 3. Denominator: 17017 = 7 * 11 * 13 * 17. Exactly 38,707,200 units in a ring of 214,414,200 elements.
6 primes
192/1001 = 19.18%
2,419,200 units. 64 idempotents. 128 involutions.
7 primes
3072/17017 = 18.05%
38,707,200 units. 128 idempotents. 256 involutions.
Factor
16/17
192/1001 * 16/17 = 3072/17017. Each new prime reduces unit density. phi(17) = 16 enters the numerator; 17 enters the denominator.
Projector
CRT = (0, 1, 1, 1, 1, 1, 1)
26,801,776 = 2^1680 mod 214,414,200. The seven-channel projector kills mod-8 and preserves six channels. Complement: 187,612,425 with CRT = (1, 0, 0, 0, 0, 0, 0).

Persistence extends: 13 and 17 both have exponent 1 (one step to self-annihilation), joining 11. The full persistence depths are {3, 2, 2, 2, 1, 1, 1} -- the Pareto exponents. 2 remains the most persistent prime. The three extension primes (11, 13, 17) are all instantaneous.

Explore: Euler Totient Ratio

Enter any N to compute phi(N)/N -- the fraction of the ring that is alive (units).

Enter N:

Try: N=214414200 (7 primes, 3072/17017), N=12612600 (6 primes, 192/1001), N=970200 (5 primes, 16/77), N=2310 (5 thin, 8/21), N=210 (4 primes, 8/35), N=30 (3 primes, 4/15).

Contrast

QuestionStandardAxiom
Unit densityphi(N)/N, a fraction192/1001. Six Euler factors, one per prime. Ratio independent of exponents.
Zero-divisorsElements without inverses80.82%. At least one CRT channel is zero. Cannot participate in full multiplication.
PersistenceNo standard notionExponents {3,2,2,2,1,1} = steps to self-annihilation. 2 survives longest (3 steps). 11 and 13 fastest (1 step each).
Projector splitAbstract algebra1 = (0,1,1,1,1,1) + (1,0,0,0,0,0). Two orthogonal idempotents summing to the identity. Product = 0.
7th primeJust another factor3072/17017 = 18.05%. Adding 17 multiplies by 16/17. Idempotents double (64 to 128). Same structure, one more channel.

Verify It Yourself

Count the units. Compute the Euler product. Every number on this page is computable in .ax.

Verify in the REPL

Source code · Public domain (CC0)

Report issue

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