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D.14.1.37 arrFlats

Procedure from library arr.lib (see arr_lib).

Usage:
size(A); A arr

Return:
[arrposet] Intersection lattice

Example:
 
LIB "arr.lib";
ring R = 0,(x(1..5)),dp;
arrFlats(arrBraid(5));
==> 
==> 
==> === Computing poset ===
==> 
==> 
==> rank: 2, expected OPS: 45, executed OPS: 60
==> Cleaned up: 35 hyperplanes
==> 
==> 
==> rank: 3, expected OPS: 300, executed OPS: 75
==> Cleaned up: 60 hyperplanes
==> 
==> 
==> rank: 4, expected OPS: 105, executed OPS: 15
==> Cleaned up: 14 hyperplanes
==> 
==> 
==> 
==> 
==> Matrix tests: 1484
==> Given Arrangement:
==> _[1]=x(1)-x(2)
==> _[2]=x(1)-x(3)
==> _[3]=x(1)-x(4)
==> _[4]=x(1)-x(5)
==> _[5]=x(2)-x(3)
==> _[6]=x(2)-x(4)
==> _[7]=x(2)-x(5)
==> _[8]=x(3)-x(4)
==> _[9]=x(3)-x(5)
==> _[10]=x(4)-x(5)
==> 
==> Corresponding poset:
==> ====== rank 1: 10 flats ======
==>  (1),  (2),  (3),  (4),  (5),  (6),  (7),  (8),  (9),  (10), 
==> ====== rank 2: 25 flats ======
==>  (1,2,5),  (1,3,6),  (1,4,7),  (1,8),  (1,9),  (1,10),  (2,3,8),  (2,4,9)\
   ,  (2,6),  (2,7),  (2,10),  (3,4,10),  (3,5),  (3,7),  (3,9),  (4,5),  (4\
   ,6),  (4,8),  (5,6,8),  (5,7,9),  (5,10),  (6,7,10),  (6,9),  (7,8),  (8,\
   9,10), 
==> ====== rank 3: 15 flats ======
==>  (1,2,3,5,6,8),  (1,2,4,5,7,9),  (1,2,5,10),  (1,3,4,6,7,10),  (1,3,6,9),\
     (1,4,7,8),  (1,8,9,10),  (2,3,4,8,9,10),  (2,3,7,8),  (2,4,6,9),  (2,6,\
   7,10),  (3,4,5,10),  (3,5,7,9),  (4,5,6,8),  (5,6,7,8,9,10), 
==> ====== rank 4: 1 flats ======
==>  (1,2,3,4,5,6,7,8,9,10), 
==> ====== rank 5: 0 flats ======
==> 
==> 
See also: arrFlats.