This file is indexed.

/usr/share/gap/lib/teachmod.g is in gap-libs 4r6p5-3.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
#############################################################################
##
#W  teachmod.g                GAP library                   Alexander Hulpke
##
##
#Y  Copyright (C) 2008 The GAP Group
##
##  This  file contains rotines that enable simplified display and turn on
##  some naive routines, which are primarily of interest in a teaching
##  context. It is made part of the general system to ensure it will be
##  always installed with GAP.
##


## FFE Display

InstallMethod(ViewObj,true,[IsFFE],100,
function(x)
  local p,d;
  if TEACHMODE<>true then
    TryNextMethod();
  fi;
  d:=DegreeFFE(x);
  p:=Characteristic(x);
  if d=1 then
    Print("ZmodnZObj(",Int(x),",",p,")");
  else
    Print("Z(",p^d,")^",LogFFE(x,Z(p^d)));
  fi;
end);

InstallMethod(String,true,[IsFFE],100,
function(x)
  local p,d;
  if TEACHMODE<>true then
    TryNextMethod();
  fi;
  d:=DegreeFFE(x);
  p:=Characteristic(x);
  if d=1 then
    return Concatenation("ZmodnZObj(",String(Int(x)),",",String(p),")");
  else
    return Concatenation("Z(",String(p^d),")^",String(LogFFE(x,Z(p^d))));
  fi;
end);

InstallMethod( ZmodnZObj, "for prime residues convert to GF(p)",
  [ IsInt, IsPosInt ],100,
function( residue, n )
  if TEACHMODE<>true then
    TryNextMethod();
  fi;
  if not IsPrimeInt(n) then
    return ZmodnZObj( ElementsFamily( FamilyObj( ZmodnZ( n ) )), residue );
  else
    return residue*Z(n)^0;
  fi;
end );


## Cyclotomics display
## Careful, this can affect the rationals!

InstallMethod(ViewObj,true,[IsCyc],100,
function(x)
local a,p, d, e, b, i;
  if IsRat(x) or TEACHMODE<>true or Conductor(x)=4 then
    TryNextMethod();
  fi;
  a:=Quadratic(x,true);
  if a=fail then
    TryNextMethod();
  fi;
  Print(a.display);
end);

# basic constructors -- if teaching mode they will default to fp groups


#############################################################################
##
#F  AbelianGroup( [<filt>, ]<ints> )  . . . . . . . . . . . . . abelian group
##
BindGlobal( "AbelianGroup", function ( arg )

  if Length(arg) = 1  then
    if ForAny(arg[1],x->x=0) or TEACHMODE=true then
      return AbelianGroupCons( IsFpGroup, arg[1] );
    else
      return AbelianGroupCons( IsPcGroup, arg[1] );
    fi;
  elif IsOperation(arg[1]) then

    if Length(arg) = 2  then
      return AbelianGroupCons( arg[1], arg[2] );

    elif Length(arg) = 3  then
      return AbelianGroupCons( arg[1], arg[2], arg[3] );
    fi;
  fi;
  Error( "usage: AbelianGroup( [<filter>, ]<ints> )" );

end );


#############################################################################
##
#F  CyclicGroup( [<filt>, ]<n> )  . . . . . . . . . . . . . . .  cyclic group
##
BindGlobal( "CyclicGroup", function ( arg )

  if Length(arg) = 1  then
    if arg[1]=infinity or TEACHMODE=true then
      return CyclicGroupCons(IsFpGroup,arg[1]);
    fi;
    return CyclicGroupCons( IsPcGroup, arg[1] );
  elif IsOperation(arg[1]) then

    if Length(arg) = 2  then
      return CyclicGroupCons( arg[1], arg[2] );

    elif Length(arg) = 3  then
      return CyclicGroupCons( arg[1], arg[2], arg[3] );
    fi;
  fi;
  Error( "usage: CyclicGroup( [<filter>, ]<size> )" );

end );


#############################################################################
##
#F  DihedralGroup( [<filt>, ]<n> )  . . . . . . . dihedral group of order <n>
##
BindGlobal( "DihedralGroup", function ( arg )

  if Length(arg) = 1  then
    if TEACHMODE=true then
      return DihedralGroupCons( IsFpGroup, arg[1] );
    else
      return DihedralGroupCons( IsPcGroup, arg[1] );
    fi;
  elif IsOperation(arg[1]) then

    if Length(arg) = 2  then
      return DihedralGroupCons( arg[1], arg[2] );

    elif Length(arg) = 3  then
      return DihedralGroupCons( arg[1], arg[2], arg[3] );
    fi;
  fi;
  Error( "usage: DihedralGroup( [<filter>, ]<size> )" );

end );


#############################################################################
##
#F  ElementaryAbelianGroup( [<filt>, ]<n> ) . . . .  elementary abelian group
##
BindGlobal( "ElementaryAbelianGroup", function ( arg )

  if Length(arg) = 1  then
    if TEACHMODE=true then
      return ElementaryAbelianGroupCons( IsFpGroup, arg[1] );
    else
      return ElementaryAbelianGroupCons( IsPcGroup, arg[1] );
    fi;
  elif IsOperation(arg[1]) then

    if Length(arg) = 2  then
      return ElementaryAbelianGroupCons( arg[1], arg[2] );

    elif Length(arg) = 3  then
      return ElementaryAbelianGroupCons( arg[1], arg[2], arg[3] );
    fi;
  fi;
  Error( "usage: ElementaryAbelianGroup( [<filter>, ]<size> )" );

end );