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NBIBDs (Nested Balanced Incomplete Block Designs)
Overview
Definition
Constructions ▼
Existence ▼
Other Nested Designs ▼
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Overview
From multiplicative d.h. subgroups
▶
From additive d.h. subgroups
Overview
Theorems
(2,6)NBIBDs
(3,6)NBIBDs
Small NBIBDs
INBIBDs
Overview
Nested 3-Designs
▶
Overview
v=8
v=12
v=16
v=18
v=20
v=21
v=22
Blocks of 9 and 3
Blocks of 15 and 3
Blocks of 15 and 5
Blocks of 21 and 3
Blocks of 21 and 7
Applet to get blocks
Construction
Example
Table of solutions
NBIBDs with v = 21
Cyclic and 1-rotational NBIBDs with v=21
v
b1
b2
r
k1
k2
Found
Where
21
105
210
20
4
2
21
70
210
20
6
2
here
21
70
140
20
6
3
here
21
42
84
20
10
5