DisplayCharTable( tbl )
DisplayCharTable( tbl, arec )
DisplayCharTable
prepares the data contained in the character table
tbl for a pretty columnwise output.
In the first form DisplayCharTable
prints all irreducible characters
of the table tbl, together with the orders of the centralizers in
factorized form and the available powermaps.
Thus it can be used to echo character tables in interactive use, being
the value of the record field Print
of a record field operations
of tbl (see Character Table Records,
Operations Records for Character Tables).
Each displayed character is given a name X.n
.
The number of columns printed at one time depends on the actual
linelength, which is restored by the function SizeScreen
(see
SizeScreen).
The first lines of the output describe the order of the centralizer of an element of the class factorized into its prime divisor.
The next line gives the name of the class. If the record field
classnames
of the table tbl is not bound, DisplayCharTable
calls the function ClassNamesCharTable
to determine the class names
and to store them on the table tbl (see ClassNamesCharTable).
Preceded by a name Pn
the next lines show the nth powermaps
of tbl in terms of the former shown class names.
Every ambiguous or unknown (see Unknown) value of the table is
displayed as a question mark ?
.
Irrational character values are not printed explicitly because the lengths of their printed representation might disturb the view. Instead of that every irrational value is indicated by a name, which is a string of a least one capital letter.
Once a name for an irrational number is found, it is used all over the
printed table. Moreover the complex conjugate and the star of an
irrationality are represented by that very name preceded by a /
resp. a *
.
The printed character table is then followed by a legend, a list identifying the occurred symbols with their actual irrational value. Occasionally this identity is supplemented by a quadratic representation of the irrationality together with the corresponding ATLAS--notation.
gap> a5:= CharTable("A5");; gap> DisplayCharTable(a5); A52 2 2 . . . 3 1 . 1 . . 5 1 . . 1 1
1a 2a 3a 5a 5b 2P 1a 1a 3a 5b 5a 3P 1a 2a 1a 5b 5a 5P 1a 2a 3a 1a 1a
X.1 1 1 1 1 1 X.2 3 -1 . A *A X.3 3 -1 . *A A X.4 4 . 1 -1 -1 X.5 5 1 -1 . .
A = -E(5)-E(5)^4 = (1-ER(5))/2 = -b5
In the second form DisplayCharTable
takes an argument record arec as
an additional argument. This record can be used to change the default
style for displaying a character as shown above. Its relevant fields
are
chars
:"X"
is replaced by "Y"
),
classes
:
centralizers
:false
,
powermap
:false
to suppress the powermaps,
letter
:"P"
for permutation
characters) to replace "X"
,
indicator
:true
enables the printing of the second Schur
indicator, a list of integers enables the printing of the corresponding
indicators.
gap> arec:= rec( chars:= 4, classes:= [a5.3a..a5.5a], > centralizers:= false, indicator:= true, powermap:= [2] );; gap> Indicator( a5, 2 );; gap> DisplayCharTable( a5, arec ); A53a 5a 2P 3a 5b 2 X.4 + 1 -1
GAP 3.4.4