[284] independent HS construction: n=50 m=175 7-regular girth 5  OK
[284] lambda_min(D) = -4.000000000; min dual degree = 7.0
[284] 7 <= 4 FALSE, margin 3.000000000 -> REFUTED  [INDEPENDENT PASS]

[290] HoffmanSingleton             n=50   m=175  -lam2min=  3.0000  m/meanG=    312.500  OK
[290] Petersen                     n=10   m=15   -lam2min=  2.0000  m/meanG=     25.000  OK
[290] Heawood(6-cage)              n=14   m=21   -lam2min=  1.4142  m/meanG=     57.909  OK
[290] C5                           n=5    m=5    -lam2min=  1.6180  m/meanG=      8.333  OK
[290] K2/P2                        n=2    m=1    -lam2min= -1.0000  m/meanG=      2.000  OK
[290] Star K1,20                   n=21   m=20   -lam2min= -0.0000  m/meanG=    178.182  OK
[290] McGee(7-cage)                n=24   m=36   -lam2min=  2.3429  m/meanG=    210.286  OK
[290] TutteCoxeter(8-cage)         n=30   m=45   -lam2min=  2.0000  m/meanG=    362.500  OK
[290] 60 random trees (2<=n<=60) pass quietly
[290] 40 random girth>=5 pruned graphs pass quietly

BATTERY 4 (independent reimplementation): ALL PASS for 284-refutation and 290-theorem.