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Presets: Koebe · z/(1−z) · z·exp(z/2) · log(1+z) · arctan(z) · sin(z) · z+z² (not starlike)
Ma-Minda extremals: cardioid · lemniscate · ℘ cardioid · 3-leaf · 4-leaf · epi-3 · epi-6

Counterexamples found with this tool

Every row is a certified disproof a run like the one above produced: a point z on |z| = r where interval arithmetic guarantees Re(zf′/f) < 0, so f cannot be starlike there. A sound witness, not a sampled point.

These are computational non-membership facts, not refutations of any published theorem - most are special functions that are starlike only on a smaller sub-disk, or synthetic test cases. We record them as honest negative results.

Filtered to Mittag-Leffler E_α. Show all →
13Counterexample facts
FamilyClosed form / ParamsProperty Representative witness zRe(zf′/f) ≤ Proven rWitnesses
Mittag-Leffler E_α
{'alpha': 1.75}
starlike 0.999*exp(i*3.153864) Re ≤ -0.0116 r ≤ 0.990
3 runs
  1. #196 · 0.999*exp(i*3.153864) · Re ≤ -0.0116 · r ≤ 0.990 · boundary_scan_polynomial
  2. #622 · 0.999*exp(i*3.147729) · Re ≤ -0.0118 · r ≤ 0.990 · boundary_scan_centered_v31
  3. #1022 · 0.999*exp(i*3.147729) · Re ≤ -0.0118 · r ≤ 0.990 · boundary_scan_centered_v31
Mittag-Leffler E_α
{'alpha': 0.2}
starlike 0.99*exp(i*5.075942) Re ≤ -0.2238 r ≤ 0.950
2 runs
  1. #605 · 0.99*exp(i*5.075942) · Re ≤ -0.2238 · r ≤ 0.950 · boundary_scan_centered_v31
  2. #1015 · 0.9900*exp(i*1.22173) · Re ≤ -0.2141 · r ≤ 0.950 · pointwise_starlike_iv
Mittag-Leffler E_α
{'alpha': 1.1}
starlike 0.95*exp(i*3.153864) Re ≤ -0.0226 r ≤ 0.900
3 runs
  1. #190 · 0.95*exp(i*3.153864) · Re ≤ -0.0226 · r ≤ 0.900 · boundary_scan_polynomial
  2. #616 · 0.95*exp(i*3.178408) · Re ≤ -0.0215 · r ≤ 0.900 · boundary_scan_centered_v31
  3. #1016 · 0.9900*exp(i*3.14159) · Re ≤ -0.0731 · r ≤ 0.900 · pointwise_starlike_iv
Mittag-Leffler E_α
{'alpha': 1.15}
starlike 0.95*exp(i*3.202952) Re ≤ -0.0500 r ≤ 0.900
3 runs
  1. #191 · 0.95*exp(i*3.202952) · Re ≤ -0.0500 · r ≤ 0.900 · boundary_scan_polynomial
  2. #617 · 0.95*exp(i*3.117049) · Re ≤ -0.0533 · r ≤ 0.900 · boundary_scan_centered_v31
  3. #1017 · 0.9900*exp(i*3.14159) · Re ≤ -0.1097 · r ≤ 0.900 · pointwise_starlike_iv
Mittag-Leffler E_α
{'alpha': 1.6}
starlike 0.95*exp(i*3.117049) Re ≤ -0.0383 r ≤ 0.900
3 runs
  1. #195 · 0.95*exp(i*3.117049) · Re ≤ -0.0383 · r ≤ 0.900 · boundary_scan_polynomial
  2. #621 · 0.95*exp(i*3.129321) · Re ≤ -0.0392 · r ≤ 0.900 · boundary_scan_centered_v31
  3. #1021 · 0.9900*exp(i*3.14159) · Re ≤ -0.1141 · r ≤ 0.900 · pointwise_starlike_iv
Mittag-Leffler E_α
{'alpha': 0.15}
starlike 0.95*exp(i*2.988195) Re ≤ -0.6999 r ≤ 0.900
2 runs
  1. #604 · 0.95*exp(i*2.988195) · Re ≤ -0.6999 · r ≤ 0.900 · boundary_scan_centered_v31
  2. #1014 · 0.9900*exp(i*-2.09440) · Re ≤ -2.5884 · r ≤ 0.900 · pointwise_starlike_iv
Mittag-Leffler E_α
{'alpha': 1.5}
starlike 0.9*exp(i*3.150797) Re ≤ -0.0009 r ≤ 0.800
3 runs
  1. #67 · 0.9*exp(i*3.150797) · Re ≤ -0.0009 · r ≤ 0.800 · boundary_scan_polynomial
  2. #595 · 0.9*exp(i*3.141976) · Re ≤ -0.0010 · r ≤ 0.800 · boundary_scan_centered_v31
  3. #986 · 0.9900*exp(i*3.14159) · Re ≤ -0.1676 · r ≤ 0.800 · pointwise_starlike_iv
Mittag-Leffler E_α
{'alpha': 1.25}
starlike 0.9*exp(i*3.104777) Re ≤ -0.0197 r ≤ 0.800
3 runs
  1. #76 · 0.9*exp(i*3.104777) · Re ≤ -0.0197 · r ≤ 0.800 · boundary_scan_polynomial
  2. #601 · 0.9*exp(i*3.153864) · Re ≤ -0.0212 · r ≤ 0.800 · boundary_scan_centered_v31
  3. #988 · 0.9900*exp(i*3.14159) · Re ≤ -0.1658 · r ≤ 0.800 · pointwise_starlike_iv
Mittag-Leffler E_α
{'alpha': 1.2}
starlike 0.9*exp(i*3.16) Re ≤ -0.0061 r ≤ 0.800
3 runs
  1. #192 · 0.9*exp(i*3.16) · Re ≤ -0.0061 · r ≤ 0.800 · boundary_scan_polynomial
  2. #618 · 0.9*exp(i*3.132389) · Re ≤ -0.0064 · r ≤ 0.800 · boundary_scan_centered_v31
  3. #1018 · 0.9900*exp(i*3.14159) · Re ≤ -0.1410 · r ≤ 0.800 · pointwise_starlike_iv
Mittag-Leffler E_α
{'alpha': 1.3}
starlike 0.9*exp(i*3.202952) Re ≤ -0.0249 r ≤ 0.800
3 runs
  1. #193 · 0.9*exp(i*3.202952) · Re ≤ -0.0249 · r ≤ 0.800 · boundary_scan_polynomial
  2. #619 · 0.9*exp(i*3.153864) · Re ≤ -0.0300 · r ≤ 0.800 · boundary_scan_centered_v31
  3. #1019 · 0.9900*exp(i*3.14159) · Re ≤ -0.1829 · r ≤ 0.800 · pointwise_starlike_iv
Mittag-Leffler E_α
{'alpha': 1.4}
starlike 0.9*exp(i*3.117049) Re ≤ -0.0272 r ≤ 0.800
3 runs
  1. #194 · 0.9*exp(i*3.117049) · Re ≤ -0.0272 · r ≤ 0.800 · boundary_scan_polynomial
  2. #620 · 0.9*exp(i*3.153864) · Re ≤ -0.0280 · r ≤ 0.800 · boundary_scan_centered_v31
  3. #1020 · 0.9900*exp(i*3.14159) · Re ≤ -0.1921 · r ≤ 0.800 · pointwise_starlike_iv
Mittag-Leffler E_α
{'alpha': 0.1}
starlike 0.9900*exp(i*-2.09440) Re ≤ -13.3170 r ≤ - 1
Mittag-Leffler E_α
{'alpha': 0.05}
starlike 0.9900*exp(i*-2.09440) Re ≤ -90.0891 r ≤ - 1
How to read a witness
z = r·exp(i·θ) is a point on the boundary circle of radius r in the unit disk. The verifier bounds Re(zf′(z)/f(z)) over a small arc around z with mpmath interval arithmetic; the upper bound shown is strictly negative, so Re(zf′/f) < 0 on the whole arc - f cannot be starlike on a disk containing z. Proven, not approximated.  Programmatic access: GET /api/v2/counterexamples
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