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atlas Library · Script File

exceptional.at

Tables of Weyl group conjugacy classes and Nilpotent Orbits
for the exceptional groups
Source
atlas-scripts/exceptional.at (175 lines)
Definitions
35
Loads
Loaded by
exceptionalNilpotentData.at

Definitions in source order

EllipticDatum type

L12
set_type EllipticDatum = (WeylElt w,[int] charpoly, int order, int length, string name, int size)

Fields: w, charpoly, order, length, name, size

data type for table of elliptic conjugacy classes
could be expanded to all conjugacy classes

EllipticTable type

L13
set_type EllipticTable=[EllipticDatum]

root_datum

L16root_datum(EllipticTable T)
table is assumed non-empty and all WeylElt are for same RootDatum

also in this file at line 63; also 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, bracket.at

lookup_by_name

L18lookup_by_name(EllipticTable T,string name) = int

also in this file at line 64

show

L22show(EllipticTable T) = void
nice output of table

also in this file at line 75; also 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, bracket.at, nilpotent_posets.at, lazy_lists.at

show_long

L29show_long(EllipticTable T) = void
include a representative of each class

also defined in character_tables.at, springer_tables.at, hodgeParamLaurentPol.at, hodgeParamPol.at, weak_packets.at, cyclotomic_Lie_algebra.at, bracket.at

NilpotentDatum type

L45
set_type NilpotentDatum=(RootDatum root_datum,string name ,string alt_name,int special,[int] closure,string dual,string A,string Abar,[int] diagram)

Fields: root_datum, name, alt_name, special, closure, dual, A, Abar, diagram

data type for a table of information about nilpotent orbits
name: according to Carter
alt_name: Spaltenstein/Mizuno etc., when different
special: 1 or 0
closure: orbits in the closure (not including itself)
dual: name of dual orbit
A: string giving A(O)
Abar: Lusztig's quotient
diagram: labeled Dynkin diagram

orbit

L46orbit(NilpotentDatum d) = ComplexNilpotent

also defined in springer_tables.at, W_reps_type_BC.at

dimension

L47dimension(NilpotentDatum d) = int

also defined in basic.at, finite_dimensional.at, K_highest_weights.at, nilpotent_orbits.at, character_tables.at, W_reps_type_BC.at, tensor_product.at

is_special

L48is_special(NilpotentDatum d) = bool

also defined in combinatorics.at, springer_tables.at, W_reps_type_BC.at

is_even

L49is_even(NilpotentDatum d) = bool

also defined in basic.at, nilpotent_orbits.at

H

L50H(NilpotentDatum d)
_of_triple

also defined in groups.at, cyclotomic_Lie_algebra.at, bracket.at

Levi

L51Levi(NilpotentDatum d) = RootDatum

also defined in parabolics.at

is_distinguished

L55is_distinguished(NilpotentDatum d) = bool

also defined in sommers.at, twisted_root_datum.at

NilpotentTable type

L62
set_type NilpotentTable=[NilpotentDatum]

root_datum

L63root_datum(NilpotentTable T) = RootDatum

also in this file at line 16; also 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, bracket.at

lookup_by_name

L64lookup_by_name(NilpotentTable T,string name) = int

also in this file at line 18

lookup_by_alt_name

L65lookup_by_alt_name(NilpotentTable T,string alt_name) = int

lookup_by_diagram

L67lookup_by_diagram(NilpotentTable T,[int] diagram) = int

long_name 2 overloads

L69long_name(NilpotentDatum row) = string
L71long_name(NilpotentTable T,int i) = string

show

L75show(NilpotentTable T) = void
nice output

also in this file at line 22; also 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, bracket.at, nilpotent_posets.at, lazy_lists.at

nilpotent_poset

L82nilpotent_poset(NilpotentTable T) = NilpotentPoset
extract NilpotentPoset from the table

also defined in nilpotent_posets.at

closure

L89closure(NilpotentTable T) = NilpotentTable
fill in all orbits in the closure of each given one (not just covering relations)

also defined in K_Nilpotent.at, poset.at

sub_table 2 overloads

L98sub_table(NilpotentTable T, [int] S) = NilpotentTable
extract table given by rows
the closure relations require work (throwing out terms and renumbering)
L106sub_table(NilpotentTable T,(NilpotentDatum->bool) selection_function) = NilpotentTable

also defined in structure_constants.at

text_save

L110text_save(NilpotentTable T,string name)
save a table in a form that can be read in by atlas

shift_closures_by_one

L120shift_closures_by_one(NilpotentTable T) = NilpotentTable
tool for fixing the closures, the source files numbered starting
at 1 not 0, this shouldn't be needed any more

graph

L127graph(NilpotentTable T,[string] labels) = string
graph from a table, with specified labels

also in this file at line 159, line 167; also defined in poset.at, nilpotent_posets.at

Commented-out code, lines 129–136 (5 lines)
{graph from a table, with labels
integer, name and alt_name (when different)
}
set graph(NilpotentTable T)=string:
graph(T, for i:#T do i.to_string + " " + T[i].name + ":" + T[i].alt_name od )

preimage

L139preimage([(string ,string)] pairs,string y) = string
given function from strings -> strings, find preimage

lusztig_graph

L146lusztig_graph(NilpotentTable T,[(string,string)] lusztig_map)
graph showing closure relations in the image of Lusztig's map from [W] to
N, restricted to elliptic elements

graph 2 overloads

L159graph(NilpotentPoset P,NilpotentTable T) = string
graph of a nilpotent poset (see nilpotent_posets.at), using
the table for the names
L167graph(NilpotentTable T) = string

also in this file at line 127; also defined in poset.at, nilpotent_posets.at

extract sub_table by rule on row, see is_special etc.
just after set_type NilpotentDatum
L170

sub_table_distinguished

L174sub_table_distinguished(NilpotentTable T) = NilpotentTable

sub_table_even

L175sub_table_even(NilpotentTable T) = NilpotentTable

Generated from atlas-scripts at commit 648506c (2026-10-13).