atlas Library · Script File
bracket.at
Lie bracket
Definitions in source order
LieAlgebraElement type
set_type LieAlgebraElement=(StructureConstantTable t,(ratvec,ratvec) X)
Fields: t, X
data type for an element of a reductive Lie algebra Q
N=number of roots
n=rank
X=ratvec of size N <-> \sum_{i=0}^{N-1} x_i X_i where X_i are the root vectors
H=ratvec of size n <-> X_* in atlas coordinates
arbitrary element of \g: (X,H)
root_datum
root_datum(LieAlgebraElement (t,)) = RootDatumalso defined in basic.at, W_reps.at, K_Nilpotent.at, sommers.at, parabolics.at, K.at, nilpotent_orbits.at, W_classes.at, extended_misc.at, character_tables.at, springer_tables.at, disconnected.at, cyclotomic_Lie_algebra.at, exceptional.at
root_part
root_part(LieAlgebraElement(,(v,))) = ratvecalso defined in cyclotomic_Lie_algebra.at
semisimple_part
semisimple_part(LieAlgebraElement(,(,v))) = ratvecalso defined in center.at, cyclotomic_Lie_algebra.at
H
H(LieAlgebraElement X) = ratvecalso in this file at line 151; also defined in groups.at, cyclotomic_Lie_algebra.at, exceptional.at
=
=(LieAlgebraElement X,LieAlgebraElement Y) = boolalso in this file at line 22; also defined in basic.at, combinatorics.at, modules.at, parabolics.at, synthetic.at, hash.at, tits.at, K_highest_weights.at, nilpotent_orbits.at, cyclotomic.at, polynomial.at, W_reps_type_BC.at, hodgeParamLaurentPol.at, hodgeParamPol.at, laurentPolynomial.at, extended.at, disconnected.at, cyclotomic_Lie_algebra.at, cyclotomicMat.at
null
null(StructureConstantTable t) = LieAlgebraElementss_
ss_?
also defined in all_finite_order.at, cyclotomic_Lie_algebra.at, cyclotomicMat.at
=
=(LieAlgebraElement X) = boolalso in this file at line 19; also defined in basic.at, combinatorics.at, modules.at, parabolics.at, synthetic.at, hash.at, tits.at, K_highest_weights.at, nilpotent_orbits.at, cyclotomic.at, polynomial.at, W_reps_type_BC.at, hodgeParamLaurentPol.at, hodgeParamPol.at, laurentPolynomial.at, extended.at, disconnected.at, cyclotomic_Lie_algebra.at, cyclotomicMat.at
+
+(LieAlgebraElement X,LieAlgebraElement Y) = LieAlgebraElementalso defined in basic.at, extParamPol.at, modules.at, ratmat.at, cyclotomic.at, polynomial.at, hodgeParamLaurentPol.at, hodgeParamPol.at, laurentPolynomial.at, cyclotomic_Lie_algebra.at, cyclotomicMat.at, hodge_functions.at, lazy_lists.at
*
*(rat c,LieAlgebraElement X) = LieAlgebraElementalso defined in basic.at, extParamPol.at, complex.at, modules.at, hodge_tensor.at, tits_centralizer.at, stable.at, synthetic.at, Weylgroup.at, group_operations.at, ratmat.at, tits.at, twisted_root_datum.at, cyclotomic.at, polynomial.at, hodgeParamLaurentPol.at, hodgeParamPol.at, laurentPolynomial.at, cyclotomic_Lie_algebra.at, cyclotomicMat.at, hodge_functions.at, sparse.at, lazy_lists.at
coordinates
coordinates(LieAlgebraElement X)(t,v,w)-> v##w
also in this file at line 63, line 69; also defined in cyclotomic_Lie_algebra.at
lie_algebra_element
lie_algebra_element(StructureConstantTable t,ratvec v)element of Lie algebra coming from ratvec of size n+N=dim(\g)
also defined in cyclotomic_Lie_algebra.at
lie_algebra_element_semisimple
lie_algebra_element_semisimple(StructureConstantTable t,ratvec v)also defined in cyclotomic_Lie_algebra.at
lie_algebra_element_root_vectors
lie_algebra_element_root_vectors(StructureConstantTable t,ratvec v)also defined in cyclotomic_Lie_algebra.at
basis
basis(StructureConstantTable t,int i) = LieAlgebraElement1\le i\le dim\g -> (t,(v,w)) where either v or w has exactly one entry 1
show
show(LieAlgebraElement X) = voidalso defined in modules.at, K_Nilpotent.at, good_W_representatives.at, arthur_parameters.at, sub_cells.at, associated_variety_annihilator.at, geck_generic.at, L_packet.at, ratmat.at, Levi_subgroups.at, nilpotent_orbits.at, subgroups.at, poset.at, cyclotomic.at, polynomial.at, character_tables.at, springer_tables.at, hodgeParamLaurentPol.at, hodgeParamPol.at, laurentPolynomial.at, weak_packets.at, cyclotomic_Lie_algebra.at, cyclotomicMat.at, exceptional.at, nilpotent_posets.at, lazy_lists.at
format
format(LieAlgebraElement X) = stringnice string representation of LieAlgebraElement
also defined in cyclotomic.at, polynomial.at, extended_misc.at, cyclotomicMat.at
root_part_array
root_part_array(LieAlgebraElement X) = [(rat,vec)]also defined in cyclotomic_Lie_algebra.at
show_long
show_long(LieAlgebraElement X) = voidalso defined in character_tables.at, springer_tables.at, hodgeParamLaurentPol.at, hodgeParamPol.at, weak_packets.at, cyclotomic_Lie_algebra.at, exceptional.at
coordinates 2 overloads
coordinates(RootDatum rd,vec alpha) = veccoordinates of X_alpha: [0,...,1,..0] (N-tuple)
coordinates(RootDatum rd) = (vec->vec)also in this file at line 31; also defined in cyclotomic_Lie_algebra.at
support
support(LieAlgebraElement X) = [vec]also defined in parabolics.at, nilpotent_orbits.at, W_reps_type_BC.at, cyclotomic_Lie_algebra.at
bracket_root_term
bracket_root_term(LieAlgebraElement X,LieAlgebraElement Y) = LieAlgebraElement[X,Y] =[(X.root_term,X.H),(Y.root_term,Y.H)]= [X.root_term,Y.root_term] + other terms this function returns just the root term of this bracket (not the torus part which may also be nonzero) this is computed from the structure constant table
also defined in cyclotomic_Lie_algebra.at
bracket_torus_term
bracket_torus_term(LieAlgebraElement X,LieAlgebraElement Y) = LieAlgebraElementtorus term, coming from [X_alpha,X_-alpha]
also defined in cyclotomic_Lie_algebra.at
bracket_off_diagonal_terms
bracket_off_diagonal_terms(LieAlgebraElement X,LieAlgebraElement Y) = LieAlgebraElement[X,Y]=(X.root_terms,X.H),(Y.root_terms,Y.H)] -> [X.H,Y.root_terms] + [X.H,Y.root_terms], which gives a term \sum_1^N a_i X_i
also defined in cyclotomic_Lie_algebra.at
bracket
bracket(LieAlgebraElement X,LieAlgebraElement Y) = LieAlgebraElementput the three bracket calculations together
also defined in cyclotomic_Lie_algebra.at
X_alpha 2 overloads
X_alpha(StructureConstantTable t,int i) = LieAlgebraElementroot -> (v,null(rank)) where v=e(N,i)=1 in i^th spot, i=# of root in rd.roots
set X_alpha(StructureConstantTable t,int i)=LieAlgebraElement:(t,(e(#t.root_datum.roots,i),null(#t.root_datum.simple_roots)))
X_alpha(StructureConstantTable t,vec alpha) = LieAlgebraElementalso defined in cyclotomic_Lie_algebra.at
H
H(StructureConstantTable t,vec h) = LieAlgebraElementH(t,h)=(t,null(N),h)
also in this file at line 18; also defined in groups.at, cyclotomic_Lie_algebra.at, exceptional.at
X 2 overloads
X(StructureConstantTable t,(vec alpha,vec h)) = LieAlgebraElement(t,alpha,h)=(t,v,h) where v=root_term(t,alpha)
X(StructureConstantTable t,vec alpha,vec h) = LieAlgebraElementalternative format
also defined in cyclotomic_Lie_algebra.at, lazy_lists.at
ad
ad(LieAlgebraElement X) = ratmatalso defined in cyclotomic_Lie_algebra.at
solve_ad
solve_ad(LieAlgebraElement X,LieAlgebraElement Z) = Maybe<ratvec>solve ad(X)(Y)=Z for Y
two_eigenspace 2 overloads
two_eigenspace(RootDatum rd,ratvec H) = [vec]2-eigenspace of ad(H): as list of roots
two_eigenspace(StructureConstantTable t,ratvec H) = [LieAlgebraElement]2-eigenspace of ad(H): as list of LieAlgebraElements
Jacobson-Morozov triples (H,X,Y)L173
JM_triple 5 overloads
JM_triple(StructureConstantTable t,vec H,int n) = (bool,(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement))complete Jacobson Morozov triple: given H, find X,Y so that [H,X]=2X, [H,Y]=-2Y, [X,Y]=H
JM_triple(StructureConstantTable t,vec H) = (bool,(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement))JM_triple(StructureConstantTable t,ComplexNilpotent O) = (bool,(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement))JM_triple(StructureConstantTable t) = (ComplexNilpotent->(bool,(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement)))JM_triple(ComplexNilpotent O) = (bool,(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement))also defined in tits_centralizer.at
try again: find all X's where all coefficients are \pm1, with the signs constant on w-orbitsL198
JM_triple_signs 4 overloads
JM_triple_signs(StructureConstantTable t,vec H) = (bool,(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement))different idea: find a triple where all coefficients are \pm 1
JM_triple_signs(StructureConstantTable t,ComplexNilpotent O) = (bool,(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement))JM_triple_signs(StructureConstantTable t) = (ComplexNilpotent->(bool,(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement)))JM_triple_signs(ComplexNilpotent O) = (bool,(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement))ALL Jacobson Morozov triples (with coefficient -1,1)L230
JM_triples_signs 2 overloads
JM_triples_signs(StructureConstantTable t,[vec] S,vec H) = [(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement)]JM_triples_signs(StructureConstantTable t,vec H) = [(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement)]JM_triple_signs 3 overloads
JM_triple_signs(StructureConstantTable t,ComplexNilpotent O) = (bool,(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement))JM_triple_signs(StructureConstantTable t) = (ComplexNilpotent->(bool,(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement)))JM_triple_signs(ComplexNilpotent O) = (bool,(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement))JM_triples 2 overloads
JM_triples(StructureConstantTable t) = [(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement)]compute all triples for rd
JM_triples(RootDatum rd) = [(LieAlgebraElement,LieAlgebraElement,LieAlgebraElement)]also defined in tits_centralizer.at
Jacobi identityL274
jacobi_formula
jacobi_formula(LieAlgebraElement X,LieAlgebraElement Y,LieAlgebraElement Z) = LieAlgebraElementgeneral Jacobi formula [[X,Y],Z]+[[Z,X],Y]+[Y,X],X]
also defined in structure_constants.at, cyclotomic_Lie_algebra.at
jacobi_identities
jacobi_identities(StructureConstantTable t) = booltest all Jacobi identities for the Lie algebra see jacobi_identity in structure_constants.at
also in this file at line 297; also defined in cyclotomic_Lie_algebra.at
jacobi_identities_long
jacobi_identities_long(StructureConstantTable t) = voidalso in this file at line 298; also defined in cyclotomic_Lie_algebra.at
jacobi_identities
jacobi_identities(RootDatum rd) = boolalso in this file at line 283; also defined in cyclotomic_Lie_algebra.at
jacobi_identities_long
jacobi_identities_long(RootDatum rd) = voidalso in this file at line 289; also defined in cyclotomic_Lie_algebra.at
centralizer
centralizer((LieAlgebraElement X,LieAlgebraElement Y))also defined in good_W_representatives.at, nilpotent_centralizer.at, K_highest_weights.at, subgroups.at, conjugate.at, cyclotomic_Lie_algebra.at, weyl_character_formula.at
embed
embed(LieAlgebraElement X_L,StructureConstantTable t_rd)embed X for L into G use this to promote triple (H,X,Y) from L up to G
L must be an equal rank subgroup of rd
also defined in cyclotomic.at, character_table_reps.at, cyclotomic_Lie_algebra.at, cyclotomicMat.at
Generated from atlas-scripts at commit 648506c (2026-10-13).
Commented-out code, lines 203–206 (2 lines)