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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 Wright φ(α,β; z). Show all →
27Counterexample facts
FamilyClosed form / ParamsProperty Representative witness zRe(zf′/f) ≤ Proven rWitnesses
Wright φ(α,β; z)
{'alpha': 1.25, 'beta': 1.5}
starlike 0.99*exp(i*3.153864) Re ≤ -0.0078 r ≤ 0.950
3 runs
  1. #361 · 0.99*exp(i*3.153864) · Re ≤ -0.0078 · r ≤ 0.950 · boundary_scan_polynomial
  2. #785 · 0.99*exp(i*3.144661) · Re ≤ -0.0081 · r ≤ 0.950 · boundary_scan_centered_v31
  3. #1115 · 0.9900*exp(i*3.14159) · Re ≤ -0.0081 · r ≤ 0.950 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.1, 'beta': 1.0}
starlike 0.95*exp(i*3.095573) Re ≤ -0.0129 r ≤ 0.900
3 runs
  1. #337 · 0.95*exp(i*3.095573) · Re ≤ -0.0129 · r ≤ 0.900 · boundary_scan_polynomial
  2. #761 · 0.95*exp(i*3.172272) · Re ≤ -0.0135 · r ≤ 0.900 · boundary_scan_centered_v31
  3. #1097 · 0.9900*exp(i*3.14159) · Re ≤ -0.0575 · r ≤ 0.900 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 1.5, 'beta': 1.25}
starlike 0.95*exp(i*3.092505) Re ≤ -0.0477 r ≤ 0.900
3 runs
  1. #366 · 0.95*exp(i*3.092505) · Re ≤ -0.0477 · r ≤ 0.900 · boundary_scan_polynomial
  2. #790 · 0.95*exp(i*3.153864) · Re ≤ -0.0538 · r ≤ 0.900 · boundary_scan_centered_v31
  3. #1119 · 0.9900*exp(i*3.14159) · Re ≤ -0.1396 · r ≤ 0.900 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.25, 'beta': 1.0}
starlike 0.9*exp(i*3.202952) Re ≤ -0.0805 r ≤ 0.800
3 runs
  1. #343 · 0.9*exp(i*3.202952) · Re ≤ -0.0805 · r ≤ 0.800 · boundary_scan_polynomial
  2. #767 · 0.9*exp(i*3.018874) · Re ≤ -0.0722 · r ≤ 0.800 · boundary_scan_centered_v31
  3. #1100 · 0.9900*exp(i*3.14159) · Re ≤ -0.2046 · r ≤ 0.800 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.5, 'beta': 0.75}
starlike 0.9*exp(i*3.104777) Re ≤ -0.0512 r ≤ 0.800
3 runs
  1. #347 · 0.9*exp(i*3.104777) · Re ≤ -0.0512 · r ≤ 0.800 · boundary_scan_polynomial
  2. #771 · 0.9*exp(i*3.067962) · Re ≤ -0.0500 · r ≤ 0.800 · boundary_scan_centered_v31
  3. #1103 · 0.9900*exp(i*3.14159) · Re ≤ -0.1502 · r ≤ 0.800 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.75, 'beta': 0.5}
starlike 0.9*exp(i*3.117049) Re ≤ -0.1024 r ≤ 0.800
3 runs
  1. #351 · 0.9*exp(i*3.117049) · Re ≤ -0.1024 · r ≤ 0.800 · boundary_scan_polynomial
  2. #775 · 0.9*exp(i*3.411573) · Re ≤ -0.0903 · r ≤ 0.800 · boundary_scan_centered_v31
  3. #1106 · 0.9900*exp(i*2.89725) · Re ≤ -0.2096 · r ≤ 0.800 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 2.0, 'beta': 0.75}
starlike 0.9*exp(i*3.19068) Re ≤ -0.0930 r ≤ 0.800
3 runs
  1. #370 · 0.9*exp(i*3.19068) · Re ≤ -0.0930 · r ≤ 0.800 · boundary_scan_polynomial
  2. #794 · 0.9*exp(i*3.166136) · Re ≤ -0.0991 · r ≤ 0.800 · boundary_scan_centered_v31
  3. #1121 · 0.9900*exp(i*3.14159) · Re ≤ -0.3478 · r ≤ 0.800 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.5, 'beta': 1.5}
starlike 0.8*exp(i*3.117049) Re ≤ -0.0621 r ≤ 0.600
3 runs
  1. #122 · 0.8*exp(i*3.117049) · Re ≤ -0.0621 · r ≤ 0.600 · boundary_scan_polynomial
  2. #757 · 0.8*exp(i*3.166136) · Re ≤ -0.0621 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1002 · 0.9900*exp(i*3.14159) · Re ≤ -0.4682 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 1.0, 'beta': 1.0}
starlike 0.8*exp(i*2.99433) Re ≤ -0.3988 r ≤ 0.600
3 runs
  1. #124 · 0.8*exp(i*2.99433) · Re ≤ -0.3988 · r ≤ 0.600 · boundary_scan_polynomial
  2. #756 · 0.8*exp(i*3.19068) · Re ≤ -0.4888 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1003 · 0.9900*exp(i*3.14159) · Re ≤ -1.5012 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.1, 'beta': 1.25}
starlike 0.8*exp(i*3.104777) Re ≤ -0.0406 r ≤ 0.600
3 runs
  1. #338 · 0.8*exp(i*3.104777) · Re ≤ -0.0406 · r ≤ 0.600 · boundary_scan_polynomial
  2. #762 · 0.8*exp(i*3.178408) · Re ≤ -0.0406 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1098 · 0.9900*exp(i*3.14159) · Re ≤ -0.3721 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.1, 'beta': 1.5}
starlike 0.8*exp(i*3.202952) Re ≤ -0.0643 r ≤ 0.600
3 runs
  1. #339 · 0.8*exp(i*3.202952) · Re ≤ -0.0643 · r ≤ 0.600 · boundary_scan_polynomial
  2. #763 · 0.8*exp(i*3.067962) · Re ≤ -0.0623 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1099 · 0.9900*exp(i*3.14159) · Re ≤ -0.4254 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.25, 'beta': 1.25}
starlike 0.8*exp(i*3.117049) Re ≤ -0.1004 r ≤ 0.600
3 runs
  1. #344 · 0.8*exp(i*3.117049) · Re ≤ -0.1004 · r ≤ 0.600 · boundary_scan_polynomial
  2. #768 · 0.8*exp(i*3.067962) · Re ≤ -0.0944 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1101 · 0.9900*exp(i*3.14159) · Re ≤ -0.4765 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.25, 'beta': 1.5}
starlike 0.8*exp(i*3.117049) Re ≤ -0.0693 r ≤ 0.600
3 runs
  1. #345 · 0.8*exp(i*3.117049) · Re ≤ -0.0693 · r ≤ 0.600 · boundary_scan_polynomial
  2. #769 · 0.8*exp(i*3.215224) · Re ≤ -0.0633 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1102 · 0.9900*exp(i*3.14159) · Re ≤ -0.4397 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.5, 'beta': 1.0}
starlike 0.8*exp(i*3.215224) Re ≤ -0.1693 r ≤ 0.600
3 runs
  1. #348 · 0.8*exp(i*3.215224) · Re ≤ -0.1693 · r ≤ 0.600 · boundary_scan_polynomial
  2. #772 · 0.8*exp(i*3.092505) · Re ≤ -0.1738 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1104 · 0.9900*exp(i*3.14159) · Re ≤ -0.6075 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.5, 'beta': 1.25}
starlike 0.8*exp(i*3.018874) Re ≤ -0.1788 r ≤ 0.600
3 runs
  1. #349 · 0.8*exp(i*3.018874) · Re ≤ -0.1788 · r ≤ 0.600 · boundary_scan_polynomial
  2. #773 · 0.8*exp(i*3.092505) · Re ≤ -0.2029 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1105 · 0.9900*exp(i*3.14159) · Re ≤ -0.7075 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.75, 'beta': 0.75}
starlike 0.8*exp(i*3.19068) Re ≤ -0.3197 r ≤ 0.600
3 runs
  1. #352 · 0.8*exp(i*3.19068) · Re ≤ -0.3197 · r ≤ 0.600 · boundary_scan_polynomial
  2. #776 · 0.8*exp(i*2.99433) · Re ≤ -0.2769 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1107 · 0.9900*exp(i*3.14159) · Re ≤ -0.8999 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.75, 'beta': 1.0}
starlike 0.8*exp(i*3.19068) Re ≤ -0.4024 r ≤ 0.600
3 runs
  1. #353 · 0.8*exp(i*3.19068) · Re ≤ -0.4024 · r ≤ 0.600 · boundary_scan_polynomial
  2. #777 · 0.8*exp(i*3.19068) · Re ≤ -0.4024 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1108 · 0.9900*exp(i*3.14159) · Re ≤ -1.1592 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.75, 'beta': 1.25}
starlike 0.8*exp(i*3.19068) Re ≤ -0.2498 r ≤ 0.600
3 runs
  1. #354 · 0.8*exp(i*3.19068) · Re ≤ -0.2498 · r ≤ 0.600 · boundary_scan_polynomial
  2. #778 · 0.8*exp(i*3.19068) · Re ≤ -0.2498 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1109 · 0.9900*exp(i*3.14159) · Re ≤ -0.8808 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 0.75, 'beta': 1.5}
starlike 0.8*exp(i*3.153864) Re ≤ -0.0054 r ≤ 0.600
3 runs
  1. #355 · 0.8*exp(i*3.153864) · Re ≤ -0.0054 · r ≤ 0.600 · boundary_scan_polynomial
  2. #779 · 0.8*exp(i*3.144661) · Re ≤ -0.0056 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1110 · 0.9900*exp(i*3.14159) · Re ≤ -0.4227 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 1.25, 'beta': 1.0}
starlike 0.8*exp(i*3.239767) Re ≤ -0.3284 r ≤ 0.600
3 runs
  1. #359 · 0.8*exp(i*3.239767) · Re ≤ -0.3284 · r ≤ 0.600 · boundary_scan_polynomial
  2. #783 · 0.8*exp(i*3.092505) · Re ≤ -0.3607 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1113 · 0.9900*exp(i*3.14159) · Re ≤ -1.2964 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 1.25, 'beta': 1.25}
starlike 0.8*exp(i*3.144661) Re ≤ -0.0007 r ≤ 0.600
3 runs
  1. #360 · 0.8*exp(i*3.144661) · Re ≤ -0.0007 · r ≤ 0.600 · boundary_scan_polynomial
  2. #784 · 0.8*exp(i*3.141784) · Re ≤ -0.0007 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1114 · 0.9900*exp(i*3.14159) · Re ≤ -0.5089 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 1.5, 'beta': 0.75}
starlike 0.8*exp(i*3.239767) Re ≤ -0.4981 r ≤ 0.600
3 runs
  1. #364 · 0.8*exp(i*3.239767) · Re ≤ -0.4981 · r ≤ 0.600 · boundary_scan_polynomial
  2. #788 · 0.8*exp(i*3.092505) · Re ≤ -0.5459 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1117 · 0.9900*exp(i*3.14159) · Re ≤ -1.8628 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 1.5, 'beta': 1.0}
starlike 0.8*exp(i*3.19068) Re ≤ -0.1037 r ≤ 0.600
3 runs
  1. #365 · 0.8*exp(i*3.19068) · Re ≤ -0.1037 · r ≤ 0.600 · boundary_scan_polynomial
  2. #789 · 0.8*exp(i*3.166136) · Re ≤ -0.1093 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1118 · 0.9900*exp(i*3.14159) · Re ≤ -0.7682 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 2.0, 'beta': 0.5}
starlike 0.8*exp(i*3.239767) Re ≤ -0.2420 r ≤ 0.600
3 runs
  1. #369 · 0.8*exp(i*3.239767) · Re ≤ -0.2420 · r ≤ 0.600 · boundary_scan_polynomial
  2. #793 · 0.8*exp(i*3.19068) · Re ≤ -0.2758 · r ≤ 0.600 · boundary_scan_centered_v31
  3. #1120 · 0.9900*exp(i*3.14159) · Re ≤ -1.2306 · r ≤ 0.600 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 1.25, 'beta': 0.5}
starlike 0.6*exp(i*3.19068) Re ≤ -0.1148 r ≤ 0.300
3 runs
  1. #357 · 0.6*exp(i*3.19068) · Re ≤ -0.1148 · r ≤ 0.300 · boundary_scan_polynomial
  2. #781 · 0.6*exp(i*3.166136) · Re ≤ -0.1197 · r ≤ 0.300 · boundary_scan_centered_v31
  3. #1111 · 0.9900*exp(i*3.14159) · Re ≤ -3.3116 · r ≤ 0.300 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 1.25, 'beta': 0.75}
starlike 0.6*exp(i*3.144661) Re ≤ -0.0004 r ≤ 0.300
3 runs
  1. #358 · 0.6*exp(i*3.144661) · Re ≤ -0.0004 · r ≤ 0.300 · boundary_scan_polynomial
  2. #782 · 0.6*exp(i*3.141784) · Re ≤ -0.0005 · r ≤ 0.300 · boundary_scan_centered_v31
  3. #1112 · 0.9900*exp(i*3.14159) · Re ≤ -2.4172 · r ≤ 0.300 · pointwise_starlike_iv
Wright φ(α,β; z)
{'alpha': 1.5, 'beta': 0.5}
starlike 0.6*exp(i*3.19068) Re ≤ -0.0888 r ≤ 0.300
3 runs
  1. #363 · 0.6*exp(i*3.19068) · Re ≤ -0.0888 · r ≤ 0.300 · boundary_scan_polynomial
  2. #787 · 0.6*exp(i*3.166136) · Re ≤ -0.0941 · r ≤ 0.300 · boundary_scan_centered_v31
  3. #1116 · 0.9900*exp(i*3.14159) · Re ≤ -3.7380 · r ≤ 0.300 · pointwise_starlike_iv
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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