`BlockDesign( `

`, `

` )`

`BlockDesign( `

`, `

`, `

` )`

Let `v` be a positive integer and `B` a non-empty list of non-empty
sorted lists of elements of `{1,..., v}`.

The first version of this function returns the block design with point-set
`{1,..., v}` and block multiset

`SortedList(`

`)`

.
For the second version of this function, we require `G` to be a group
of permutations of `{1,..., v}`, and the function returns the
block design with point-set

gap> BlockDesign( 2, [[1,2],[1],[1,2]] ); rec( isBlockDesign := true, v := 2, blocks := [ [ 1 ], [ 1, 2 ], [ 1, 2 ] ] ) gap> D:=BlockDesign(7, [[1,2,4]], Group((1,2,3,4,5,6,7))); rec( isBlockDesign := true, v := 7, blocks := [ [ 1, 2, 4 ], [ 1, 3, 7 ], [ 1, 5, 6 ], [ 2, 3, 5 ], [ 2, 6, 7 ], [ 3, 4, 6 ], [ 4, 5, 7 ] ], autSubgroup := Group([ (1,2,3,4,5,6,7) ]) ) gap> AllTDesignLambdas(D); [ 7, 3, 1 ]

`AGPointFlatBlockDesign( `

`, `

`, `

` )`

Let `n` be positive integer, `q` a prime-power, and `d` a non-negative
integer less than or equal to `n`. Then this function returns the block
design whose points are the points of the affine space `AG( n,q)`,
and whose blocks are the

Note that the **affine space** `AG( n,q)` consists of all the cosets of
all the subspaces of the vector space

gap> D:=AGPointFlatBlockDesign(2,4,1); rec( isBlockDesign := true, v := 16, blocks := [ [ 1, 2, 3, 4 ], [ 1, 5, 9, 13 ], [ 1, 6, 11, 16 ], [ 1, 7, 12, 14 ], [ 1, 8, 10, 15 ], [ 2, 5, 12, 15 ], [ 2, 6, 10, 14 ], [ 2, 7, 9, 16 ], [ 2, 8, 11, 13 ], [ 3, 5, 10, 16 ], [ 3, 6, 12, 13 ], [ 3, 7, 11, 15 ], [ 3, 8, 9, 14 ], [ 4, 5, 11, 14 ], [ 4, 6, 9, 15 ], [ 4, 7, 10, 13 ], [ 4, 8, 12, 16 ], [ 5, 6, 7, 8 ], [ 9, 10, 11, 12 ], [ 13, 14, 15, 16 ] ], autSubgroup := Group([ (5,9,13)(6,10,14)(7,11,15)(8,12,16), (2,5,6)(3,9,11)(4,13,16)(7,14,12)(8,10,15), (1,5)(2,6)(3,7)(4,8)(9,13)(10,14)(11,15)(12,16), (3,4)(7,8)(9,13)(10,14)(11,16)(12,15) ]), pointNames := [ [ 0*Z(2), 0*Z(2) ], [ 0*Z(2), Z(2)^0 ], [ 0*Z(2), Z(2^2) ], [ 0*Z(2), Z(2^2)^2 ], [ Z(2)^0, 0*Z(2) ], [ Z(2)^0, Z(2)^0 ], [ Z(2)^0, Z(2^2) ], [ Z(2)^0, Z(2^2)^2 ], [ Z(2^2), 0*Z(2) ], [ Z(2^2), Z(2)^0 ], [ Z(2^2), Z(2^2) ], [ Z(2^2), Z(2^2)^2 ], [ Z(2^2)^2, 0*Z(2) ], [ Z(2^2)^2, Z(2)^0 ], [ Z(2^2)^2, Z(2^2) ], [ Z(2^2)^2, Z(2^2)^2 ] ] ) gap> AllTDesignLambdas(D); [ 20, 5, 1 ]

`PGPointFlatBlockDesign( `

`, `

`, `

` )`

Let `n` be a non-negative integer, `q` a prime-power, and `d` a
non-negative integer less than or equal to `n`. Then this function
returns the block design whose points are the (projective) points of
the projective space `PG( n,q)`, and whose blocks are the

Note that the **projective space** `PG( n,q)` consists of all the
subspaces of the vector space

gap> D:=PGPointFlatBlockDesign(3,2,1); rec( isBlockDesign := true, v := 15, blocks := [ [ 1, 2, 3 ], [ 1, 4, 5 ], [ 1, 6, 7 ], [ 1, 8, 9 ], [ 1, 10, 11 ], [ 1, 12, 13 ], [ 1, 14, 15 ], [ 2, 4, 6 ], [ 2, 5, 7 ], [ 2, 8, 10 ], [ 2, 9, 11 ], [ 2, 12, 14 ], [ 2, 13, 15 ], [ 3, 4, 7 ], [ 3, 5, 6 ], [ 3, 8, 11 ], [ 3, 9, 10 ], [ 3, 12, 15 ], [ 3, 13, 14 ], [ 4, 8, 12 ], [ 4, 9, 13 ], [ 4, 10, 14 ], [ 4, 11, 15 ], [ 5, 8, 13 ], [ 5, 9, 12 ], [ 5, 10, 15 ], [ 5, 11, 14 ], [ 6, 8, 14 ], [ 6, 9, 15 ], [ 6, 10, 12 ], [ 6, 11, 13 ], [ 7, 8, 15 ], [ 7, 9, 14 ], [ 7, 10, 13 ], [ 7, 11, 12 ] ], autSubgroup := Group([ (8,12)(9,13)(10,14)(11,15), (1,2,4,8)(3,6,12,9)(5,10)(7,14,13,11) ]), pointNames := [ <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)> ] ) gap> AllTDesignLambdas(D); [ 35, 7, 1 ]

`WittDesign( `

` )`

Suppose ` nin{9,10,11,12,21,22,23,24}`.

If ` n=24` then this function returns the

If ` n=12` then this function returns the

gap> W24:=WittDesign(24);; gap> AllTDesignLambdas(W24); [ 759, 253, 77, 21, 5, 1 ] gap> DisplayCompositionSeries(AutomorphismGroup(W24)); G (3 gens, size 244823040) | M(24) 1 (0 gens, size 1) gap> W10:=WittDesign(10);; gap> AllTDesignLambdas(W10); [ 30, 12, 4, 1 ] gap> DisplayCompositionSeries(AutomorphismGroup(W10)); G (4 gens, size 1440) | Z(2) S (4 gens, size 720) | Z(2) S (3 gens, size 360) | A(6) ~ A(1,9) = L(2,9) ~ B(1,9) = O(3,9) ~ C(1,9) = S(2,9) ~ 2A(1,9) = U(2,\ 9) 1 (0 gens, size 1)

`DualBlockDesign( `

` )`

Suppose `D` is a block design for which every point lies on at least
one block. Then this function returns the dual of `D`, the block design
in which the roles of points and blocks are interchanged, but incidence
(including repeated incidence) stays the same. Note that, since the
list of blocks of a block design is always sorted, the block list of
the dual of the dual of `D` may not be equal to the block list of `D`.

gap> D:=BlockDesign(4,[[1,3],[2,3,4],[3,4]]);; gap> dualD:=DualBlockDesign(D); rec( isBlockDesign := true, v := 3, blocks := [ [ 1 ], [ 1, 2, 3 ], [ 2 ], [ 2, 3 ] ], pointNames := [ [ 1, 3 ], [ 2, 3, 4 ], [ 3, 4 ] ] ) gap> DualBlockDesign(dualD).blocks; [ [ 1, 2 ], [ 2, 3, 4 ], [ 2, 4 ] ]

`ComplementBlocksBlockDesign( `

` )`

Suppose `D` is a binary incomplete-block design.
Then this function returns the block design on the same
point-set as `D`, whose blocks are the complements of
those of `D` (complemented with respect to the point-set).

gap> D:=PGPointFlatBlockDesign(2,2,1); rec( isBlockDesign := true, v := 7, pointNames := [ <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)> ], blocks := [ [ 1, 2, 3 ], [ 1, 4, 5 ], [ 1, 6, 7 ], [ 2, 4, 6 ], [ 2, 5, 7 ], [ 3, 4, 7 ], [ 3, 5, 6 ] ] ) gap> AllTDesignLambdas(D); [ 7, 3, 1 ] gap> C:=ComplementBlocksBlockDesign(D); rec( isBlockDesign := true, v := 7, blocks := [ [ 1, 2, 4, 7 ], [ 1, 2, 5, 6 ], [ 1, 3, 4, 6 ], [ 1, 3, 5, 7 ], [ 2, 3, 4, 5 ], [ 2, 3, 6, 7 ], [ 4, 5, 6, 7 ] ], pointNames := [ <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)>, <vector space of dimension 1 over GF(2)> ] ) gap> AllTDesignLambdas(C); [ 7, 4, 2 ]

`DeletedPointsBlockDesign( `

`, `

` )`

Suppose `D` is a block design and `Y` is a proper subset of the point-set
of `D`.

Then this function returns the block design `DP` obtained from `D` by
deleting the points in `Y` from the point-set, and from each block.
It is an error if the resulting design contains an empty block.
The points of `DP` are relabelled `1,2,...`, preserving the order of
the corresponding points of `D`; the point-names of `DP` (listed in
`DP``.pointNames`

) are those of these corresponding points of `D`.

gap> D:=BlockDesigns(rec(v:=11,blockSizes:=[5], > tSubsetStructure:=rec(t:=2,lambdas:=[2])))[1]; rec( isBlockDesign := true, v := 11, blocks := [ [ 1, 2, 3, 4, 5 ], [ 1, 2, 9, 10, 11 ], [ 1, 3, 6, 7, 9 ], [ 1, 4, 7, 8, 10 ], [ 1, 5, 6, 8, 11 ], [ 2, 3, 6, 8, 10 ], [ 2, 4, 6, 7, 11 ], [ 2, 5, 7, 8, 9 ], [ 3, 4, 8, 9, 11 ], [ 3, 5, 7, 10, 11 ], [ 4, 5, 6, 9, 10 ] ], tSubsetStructure := rec( t := 2, lambdas := [ 2 ] ), isBinary := true, isSimple := true, blockSizes := [ 5 ], blockNumbers := [ 11 ], r := 5, autGroup := Group([ (2,4)(3,5)(7,11)(8,9), (1,3)(2,5)(7,9)(10,11), (1,5,3)(6,11,7)(8,10,9), (1,10,5,2,11,3)(4,9,7)(6,8) ]) ) gap> AllTDesignLambdas(D); [ 11, 5, 2 ] gap> DP:=DeletedPointsBlockDesign(D,[5,8]); rec( isBlockDesign := true, v := 9, blocks := [ [ 1, 2, 3, 4 ], [ 1, 2, 7, 8, 9 ], [ 1, 3, 5, 6, 7 ], [ 1, 4, 6, 8 ], [ 1, 5, 9 ], [ 2, 3, 5, 8 ], [ 2, 4, 5, 6, 9 ], [ 2, 6, 7 ], [ 3, 4, 7, 9 ], [ 3, 6, 8, 9 ], [ 4, 5, 7, 8 ] ], pointNames := [ 1, 2, 3, 4, 6, 7, 9, 10, 11 ] ) gap> PairwiseBalancedLambda(DP); 2

`DeletedBlocksBlockDesign( `

`, `

`)`

Suppose `D` is a block design, and `Y` is a proper sublist of the
block-list of `D` (`Y` need not be sorted).

Then this function returns the block design obtained from `D` by deleting
the blocks in `Y` (counting repeats) from the block-list of `D`.

gap> D:=BlockDesign(7,[[1,2,4],[1,2,4]],Group((1,2,3,4,5,6,7))); rec( isBlockDesign := true, v := 7, blocks := [ [ 1, 2, 4 ], [ 1, 2, 4 ], [ 1, 3, 7 ], [ 1, 3, 7 ], [ 1, 5, 6 ], [ 1, 5, 6 ], [ 2, 3, 5 ], [ 2, 3, 5 ], [ 2, 6, 7 ], [ 2, 6, 7 ], [ 3, 4, 6 ], [ 3, 4, 6 ], [ 4, 5, 7 ], [ 4, 5, 7 ] ], autSubgroup := Group([ (1,2,3,4,5,6,7) ]) ) gap> DeletedBlocksBlockDesign(D,[[2,3,5],[2,3,5],[4,5,7]]); rec( isBlockDesign := true, v := 7, blocks := [ [ 1, 2, 4 ], [ 1, 2, 4 ], [ 1, 3, 7 ], [ 1, 3, 7 ], [ 1, 5, 6 ], [ 1, 5, 6 ], [ 2, 6, 7 ], [ 2, 6, 7 ], [ 3, 4, 6 ], [ 3, 4, 6 ], [ 4, 5, 7 ] ] )

`AddedPointBlockDesign( `

`, `

` )`

`AddedPointBlockDesign( `

`, `

`, `

` )`

Suppose `D` is a block design, and `Y` is a sublist of the block-list
of `D` (`Y` need not be sorted).

Then this function returns the block design obtained from `D` by adding
the new point `D``.v+1`

to the point-set, and adding this new point
(once) to each block of `Y` (where repeats count).

The optional parameter `pointname` specifies a point-name for the
new point.

gap> D:=BlockDesign(7,[[1,2,4],[1,2,4]],Group((1,2,3,4,5,6,7))); rec( isBlockDesign := true, v := 7, blocks := [ [ 1, 2, 4 ], [ 1, 2, 4 ], [ 1, 3, 7 ], [ 1, 3, 7 ], [ 1, 5, 6 ], [ 1, 5, 6 ], [ 2, 3, 5 ], [ 2, 3, 5 ], [ 2, 6, 7 ], [ 2, 6, 7 ], [ 3, 4, 6 ], [ 3, 4, 6 ], [ 4, 5, 7 ], [ 4, 5, 7 ] ], autSubgroup := Group([ (1,2,3,4,5,6,7) ]) ) gap> AddedPointBlockDesign(D,[[2,3,5],[2,3,5],[4,5,7]],"infinity"); rec( isBlockDesign := true, v := 8, blocks := [ [ 1, 2, 4 ], [ 1, 2, 4 ], [ 1, 3, 7 ], [ 1, 3, 7 ], [ 1, 5, 6 ], [ 1, 5, 6 ], [ 2, 3, 5, 8 ], [ 2, 3, 5, 8 ], [ 2, 6, 7 ], [ 2, 6, 7 ], [ 3, 4, 6 ], [ 3, 4, 6 ], [ 4, 5, 7 ], [ 4, 5, 7, 8 ] ], pointNames := [ 1, 2, 3, 4, 5, 6, 7, "infinity" ] )

`AddedBlocksBlockDesign( `

`, `

` )`

Suppose `Y` is a list of multisets of points of the block design `D`.
Then this function returns a new block design, whose point-set is that
of `D`, and whose block list is that of `D` with the elements of `Y`
(including repeats) added.

gap> D:=BlockDesign(7,[[1,2,4]],Group((1,2,3,4,5,6,7))); rec( isBlockDesign := true, v := 7, blocks := [ [ 1, 2, 4 ], [ 1, 3, 7 ], [ 1, 5, 6 ], [ 2, 3, 5 ], [ 2, 6, 7 ], [ 3, 4, 6 ], [ 4, 5, 7 ] ], autSubgroup := Group([ (1,2,3,4,5,6,7) ]) ) gap> AddedBlocksBlockDesign(D,D.blocks); rec( isBlockDesign := true, v := 7, blocks := [ [ 1, 2, 4 ], [ 1, 2, 4 ], [ 1, 3, 7 ], [ 1, 3, 7 ], [ 1, 5, 6 ], [ 1, 5, 6 ], [ 2, 3, 5 ], [ 2, 3, 5 ], [ 2, 6, 7 ], [ 2, 6, 7 ], [ 3, 4, 6 ], [ 3, 4, 6 ], [ 4, 5, 7 ], [ 4, 5, 7 ] ] )

`DerivedBlockDesign( `

`, `

` )`

Suppose `D` is a block design, and `x` is a point or block of `D`.
Then this function returns the **derived design**indexderived design
`DD` of `D`, with respect to `x`.

If `x` is a point then `DD` is the block design whose blocks are those
of `D` containing `x`, but with `x` deleted from these blocks, and the
points of `DD` are those which occur in some block of `DD`.

If `x` is a block, then the points of `DD` are the points in `x`, and
the blocks of `DD` are the blocks of `D` other than `x` containing at
least one point of `x`, but with all points not in `x` deleted from
these blocks. Note that any repeat of `x`, but not `x` itself, is a
block of `DD`.

It is an error if the resulting block design `DD` has no blocks or an
empty block.

The points of `DD` are relabelled `1,2,...`, preserving the order of
the corresponding points of `D`; the point-names of `DD` (listed in
`DD``.pointNames`

) are those of these corresponding points of `D`.

gap> D:=BlockDesigns(rec(v:=11,blockSizes:=[5], > tSubsetStructure:=rec(t:=2,lambdas:=[2])))[1]; rec( isBlockDesign := true, v := 11, blocks := [ [ 1, 2, 3, 4, 5 ], [ 1, 2, 9, 10, 11 ], [ 1, 3, 6, 7, 9 ], [ 1, 4, 7, 8, 10 ], [ 1, 5, 6, 8, 11 ], [ 2, 3, 6, 8, 10 ], [ 2, 4, 6, 7, 11 ], [ 2, 5, 7, 8, 9 ], [ 3, 4, 8, 9, 11 ], [ 3, 5, 7, 10, 11 ], [ 4, 5, 6, 9, 10 ] ], tSubsetStructure := rec( t := 2, lambdas := [ 2 ] ), isBinary := true, isSimple := true, blockSizes := [ 5 ], blockNumbers := [ 11 ], r := 5, autGroup := Group([ (2,4)(3,5)(7,11)(8,9), (1,3)(2,5)(7,9)(10,11), (1,5,3)(6,11,7)(8,10,9), (1,10,5,2,11,3)(4,9,7)(6,8) ]) ) gap> AllTDesignLambdas(D); [ 11, 5, 2 ] gap> DD:=DerivedBlockDesign(D,6); rec( isBlockDesign := true, v := 10, blocks := [ [ 1, 3, 6, 8 ], [ 1, 5, 7, 10 ], [ 2, 3, 7, 9 ], [ 2, 4, 6, 10 ], [ 4, 5, 8, 9 ] ], pointNames := [ 1, 2, 3, 4, 5, 7, 8, 9, 10, 11 ] ) gap> AllTDesignLambdas(DD); [ 5, 2 ] gap> DD:=DerivedBlockDesign(D,D.blocks[6]); rec( isBlockDesign := true, v := 5, blocks := [ [ 1, 2 ], [ 1, 3 ], [ 1, 4 ], [ 1, 5 ], [ 2, 3 ], [ 2, 4 ], [ 2, 5 ], [ 3, 4 ], [ 3, 5 ], [ 4, 5 ] ], pointNames := [ 2, 3, 6, 8, 10 ] ) gap> AllTDesignLambdas(DD); [ 10, 4, 1 ]

`ResidualBlockDesign( `

`, `

` )`

Suppose `D` is a block design, and `x` is a point or block of `D`.
Then this function returns the **residual design**indexresidual design
`RD` of `D`, with respect to `x`.

If `x` is a point then `RD` is the block design whose blocks are those
of `D` not containing `x`, and the points of `RD` are those which occur
in some block of `RD`.

If `x` is a block, then the points of `RD` are those of `D` not in
`x`, and the blocks of `RD` are the blocks of `D` (including repeats)
containing at least one point not in `x`, but with all points in `x`
deleted from these blocks.

It is an error if the resulting block design `RD` has no blocks.

The points of `RD` are relabelled `1,2,...`, preserving the order of
the corresponding points of `D`; the point-names of `RD` (listed in
`RD``.pointNames`

) are those of these corresponding points of `D`.

gap> D:=BlockDesigns(rec(v:=11,blockSizes:=[5], > tSubsetStructure:=rec(t:=2,lambdas:=[2])))[1]; rec( isBlockDesign := true, v := 11, blocks := [ [ 1, 2, 3, 4, 5 ], [ 1, 2, 9, 10, 11 ], [ 1, 3, 6, 7, 9 ], [ 1, 4, 7, 8, 10 ], [ 1, 5, 6, 8, 11 ], [ 2, 3, 6, 8, 10 ], [ 2, 4, 6, 7, 11 ], [ 2, 5, 7, 8, 9 ], [ 3, 4, 8, 9, 11 ], [ 3, 5, 7, 10, 11 ], [ 4, 5, 6, 9, 10 ] ], tSubsetStructure := rec( t := 2, lambdas := [ 2 ] ), isBinary := true, isSimple := true, blockSizes := [ 5 ], blockNumbers := [ 11 ], r := 5, autGroup := Group([ (2,4)(3,5)(7,11)(8,9), (1,3)(2,5)(7,9)(10,11), (1,5,3)(6,11,7)(8,10,9), (1,10,5,2,11,3)(4,9,7)(6,8) ]) ) gap> AllTDesignLambdas(D); [ 11, 5, 2 ] gap> RD:=ResidualBlockDesign(D,6); rec( isBlockDesign := true, v := 10, blocks := [ [ 1, 2, 3, 4, 5 ], [ 1, 2, 8, 9, 10 ], [ 1, 4, 6, 7, 9 ], [ 2, 5, 6, 7, 8 ], [ 3, 4, 7, 8, 10 ], [ 3, 5, 6, 9, 10 ] ], pointNames := [ 1, 2, 3, 4, 5, 7, 8, 9, 10, 11 ] ) gap> AllTDesignLambdas(RD); [ 6, 3 ] gap> RD:=ResidualBlockDesign(D,D.blocks[6]); rec( isBlockDesign := true, v := 6, blocks := [ [ 1, 2, 3 ], [ 1, 2, 4 ], [ 1, 3, 6 ], [ 1, 4, 5 ], [ 1, 5, 6 ], [ 2, 3, 5 ], [ 2, 4, 6 ], [ 2, 5, 6 ], [ 3, 4, 5 ], [ 3, 4, 6 ] ], pointNames := [ 1, 4, 5, 7, 9, 11 ] ) gap> AllTDesignLambdas(RD); [ 10, 5, 2 ]

`TDesignFromTBD( `

`, `

`, `

` )`

For `t` a non-negative integer, `K` a set of positive integers, and
`v,lambda` positive integers with `tlev`, a `t`-**wise balanced design**,
or a `t`-`(v,K,lambda)` **design**, is a binary block design with exactly
`v` points, such that each block has size in `K` and each `t`-subset of
the points is contained in exactly `lambda` blocks.

Now let `t` and `k` be positive integers, `D` be a `t`-`(v,K,lambda)`
design (for some set `K`), and ` tleklek_{1}`, where exactly

The point set of `D ^{*}` is that of

It is shown in McSo that `D ^{*}` is a

gap> D:=BlockDesigns(rec(v:=10, blockSizes:=[3,4], > tSubsetStructure:=rec(t:=2,lambdas:=[1])))[1]; rec( isBlockDesign := true, v := 10, blocks := [ [ 1, 2, 3, 4 ], [ 1, 5, 6, 7 ], [ 1, 8, 9, 10 ], [ 2, 5, 10 ], [ 2, 6, 8 ], [ 2, 7, 9 ], [ 3, 5, 9 ], [ 3, 6, 10 ], [ 3, 7, 8 ], [ 4, 5, 8 ], [ 4, 6, 9 ], [ 4, 7, 10 ] ], tSubsetStructure := rec( t := 2, lambdas := [ 1 ] ), isBinary := true, isSimple := true, blockSizes := [ 3, 4 ], blockNumbers := [ 9, 3 ], autGroup := Group([ (5,6,7)(8,9,10), (2,3)(5,7)(8,10), (2,3,4)(5,7,6)(8,9,10), (2,3,4)(5,9,6,8,7,10), (2,6,9,3,7,10)(4,5,8) ]) ) gap> PairwiseBalancedLambda(D); 1 gap> Dstar:=TDesignFromTBD(D,2,3); rec( isBlockDesign := true, v := 10, blocks := [ [ 1, 2, 3 ], [ 1, 2, 4 ], [ 1, 3, 4 ], [ 1, 5, 6 ], [ 1, 5, 7 ], [ 1, 6, 7 ], [ 1, 8, 9 ], [ 1, 8, 10 ], [ 1, 9, 10 ], [ 2, 3, 4 ], [ 2, 5, 10 ], [ 2, 5, 10 ], [ 2, 6, 8 ], [ 2, 6, 8 ], [ 2, 7, 9 ], [ 2, 7, 9 ], [ 3, 5, 9 ], [ 3, 5, 9 ], [ 3, 6, 10 ], [ 3, 6, 10 ], [ 3, 7, 8 ], [ 3, 7, 8 ], [ 4, 5, 8 ], [ 4, 5, 8 ], [ 4, 6, 9 ], [ 4, 6, 9 ], [ 4, 7, 10 ], [ 4, 7, 10 ], [ 5, 6, 7 ], [ 8, 9, 10 ] ], autGroup := Group([ (5,6,7)(8,9,10), (2,3)(5,7)(8,10), (2,3,4)(5,7,6)(8,9, 10), (2,3,4)(5,9,6,8,7,10), (2,6,9,3,7,10)(4,5,8) ]) ) gap> AllTDesignLambdas(Dstar); [ 30, 9, 2 ]

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design manual

November 2011