  
  [1X4 [33X[0;0YCreating Quasigroups and Loops[133X[101X
  
  [33X[0;0YIn  this chapter we describe several ways in which quasigroups and loops can
  be created in [5XLOOPS[105X.[133X
  
  
  [1X4.1 [33X[0;0YAbout Cayley Tables[133X[101X
  
  [33X[0;0YLet  [22XX={x_1,dots,x_n}[122X be a set and [22X⋅[122X a binary operation on [22XX[122X. Then an [22Xn[122X by [22Xn[122X
  array  with rows and columns bordered by [22Xx_1[122X, [22Xdots[122X, [22Xx_n[122X, in this order, is a
  [13XCayley  table[113X,  or  a [13Xmultiplication table[113X of [22X⋅[122X, if the entry in the row [22Xx_i[122X
  and column [22Xx_j[122X is [22Xx_i⋅ x_j[122X.[133X
  
  [33X[0;0YA Cayley table is a [13Xquasigroup table[113X if it is a latin square, i.e., if every
  entry [22Xx_i[122X appears in every column and every row exactly once.[133X
  
  [33X[0;0YAn unfortunate feature of multiplication tables in practice is that they are
  often  not  bordered,  that is, it is up to the reader to figure out what is
  meant.  Throughout this manual and in [5XLOOPS[105X, we therefore make the following
  assumption:  [13XAll  distinct  entries  in  a quasigroup table must be positive
  integers,  say [22Xx_1 < x_2 < ⋯ < x_n[122X, and if no border is specified, we assume
  that the table is bordered by [22Xx_1[122X, [22Xdots[122X, [22Xx_n[122X, in this order.[113X Note that we do
  not  assume  that  the  distinct entries [22Xx_1[122X, [22Xdots[122X, [22Xx_n[122X form the interval [22X1[122X,
  [22Xdots[122X,  [22Xn[122X.  The significance of this observation will become clear in Chapter
  [14X6[114X.[133X
  
  [33X[0;0YFinally, we say that a quasigroup table is a [13Xloop table[113X if the first row and
  the  first  column  are  the  same,  and if the entries in the first row are
  ordered in an ascending fashion.[133X
  
  
  [1X4.2 [33X[0;0YTesting Cayley Tables[133X[101X
  
  
  [1X4.2-1 [33X[0;0YIsQuasigroupTable and IsQuasigroupCayleyTable[133X[101X
  
  [29X[2XIsQuasigroupTable[102X( [3XT[103X ) [32X operation
  [29X[2XIsQuasigroupCayleyTable[102X( [3XT[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10Y[10Xtrue[110X if [3XT[103X is a quasigroup table as defined above, else [10Xfalse[110X.[133X
  
  
  [1X4.2-2 [33X[0;0YIsLoopTable and IsLoopCayleyTable[133X[101X
  
  [29X[2XIsLoopTable[102X( [3XT[103X ) [32X operation
  [29X[2XIsLoopCayleyTable[102X( [3XT[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10Y[10Xtrue[110X if [3XT[103X is a loop table as defined above, else [10Xfalse[110X.[133X
  
  [33X[0;0Y[12XRemark:[112XThe  package  [5XGUAVA[105X  also  contains  operations  dealing  with  latin
  squares. In particular, [10XIsLatinSquare[110X is declared in [5XGUAVA[105X.[133X
  
  
  [1X4.3 [33X[0;0YCanonical and Normalized Cayley Tables[133X[101X
  
  [1X4.3-1 CanonicalCayleyTable[101X
  
  [29X[2XCanonicalCayleyTable[102X( [3XT[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YCanonical   Cayley  table  constructed  from  Cayley  table  [3XT[103X  by
            replacing entries [22Xx_i[122X with [22Xi[122X.[133X
  
  [33X[0;0YA  Cayley  table is said to be [13Xcanonical[113X if it is based on elements [22X1[122X, [22Xdots[122X,
  [22Xn[122X. Although we do not assume that every quasigroup table is canonical, it is
  often desirable to present quasigroup tables in canonical way.[133X
  
  [1X4.3-2 CanonicalCopy[101X
  
  [29X[2XCanonicalCopy[102X( [3XQ[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YA canonical copy of the quasigroup or loop [3XQ[103X.[133X
  
  [33X[0;0YThis is a shorthand for [10XQuasigroupByCayleyTable(CanonicalCayleyTable([3XQ[103X[10X)[110X when
  [3XQ[103X  is  a  declared quasigroup, and [10XLoopByCayleyTable(CanonicalCayleyTable([3XQ[103X[10X)[110X
  when [3XQ[103X is a loop.[133X
  
  [1X4.3-3 NormalizedQuasigroupTable[101X
  
  [29X[2XNormalizedQuasigroupTable[102X( [3XT[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YA normalized version of the Cayley table [3XT[103X.[133X
  
  [33X[0;0YA  given  Cayley  table  [3XT[103X  is  normalized in three steps as follows: first,
  [10XCanonicalCayleyTable[110X  is  called  to  rename entries to [22X1[122X, [22Xdots[122X, [22Xn[122X, then the
  columns  of  [3XT[103X  are  permuted  so  that  the first row reads [22X1[122X, [22Xdots[122X, [22Xn[122X, and
  finally  the  rows of [3XT[103X are permuted so that the first column reads [22X1[122X, [22Xdots[122X,
  [22Xn[122X.[133X
  
  
  [1X4.4 [33X[0;0YCreating Quasigroups and Loops From Cayley Tables[133X[101X
  
  
  [1X4.4-1 [33X[0;0YQuasigroupByCayleyTable and LoopByCayleyTable[133X[101X
  
  [29X[2XQuasigroupByCayleyTable[102X( [3XT[103X ) [32X operation
  [29X[2XLoopByCayleyTable[102X( [3XT[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YThe  quasigroup  (resp.  loop)  with  quasigroup table (resp. loop
            table) [3XT[103X.[133X
  
  [33X[0;0YSince  [10XCanonicalCayleyTable[110X  is  called  within  the  above  operation,  the
  resulting  quasigroup  will have Cayley table with distinct entries [22X1[122X, [22Xdots[122X,
  [22Xn[122X.[133X
  
  [4X[32X  Example  [32X[104X
    [4X[25Xgap>[125X [27Xct := CanonicalCayleyTable( [[5,3],[3,5]] );
[127X[104X
    [4X[28X[ [ 2, 1 ], [ 1, 2 ] ]
[128X[104X
    [4X[25Xgap>[125X [27XNormalizedQuasigroupTable( ct );
[127X[104X
    [4X[28X[ [ 1, 2 ], [ 2, 1 ] ]
[128X[104X
    [4X[25Xgap>[125X [27XLoopByCayleyTable( last );
[127X[104X
    [4X[28X<loop of order 2>
[128X[104X
    [4X[25Xgap>[125X [27X[ IsQuasigroupTable( ct ), IsLoopTable( ct ) ];
[127X[104X
    [4X[28X[ true, false ]
[128X[104X
  [4X[32X[104X
  
  
  [1X4.5 [33X[0;0YCreating Quasigroups and Loops from a File[133X[101X
  
  [33X[0;0YTyping  a large multiplication table manually is tedious and error-prone. We
  have  therefore included a general method in [5XLOOPS[105X that reads multiplication
  tables of quasigroups from a file.[133X
  
  [33X[0;0YInstead  of  writing  a  separate  algorithm  for  each  common  format, our
  algorithm relies on the user to provide a bit of information about the input
  file.  Here  is  an outline of the algorithm, with file named [3Xfilename[103X and a
  string [3Xdel[103X as input (in essence, the characters of [3Xdel[103X will be ignored while
  reading the file):[133X
  
  [30X    [33X[0;6Yread the entire content of [3Xfilename[103X into a string [3Xs[103X,[133X
  
  [30X    [33X[0;6Yreplace all end-of-line characters in [3Xs[103X by spaces,[133X
  
  [30X    [33X[0;6Yreplace by spaces all characters of [3Xs[103X that appear in [3Xdel[103X,[133X
  
  [30X    [33X[0;6Ysplit [3Xs[103X into maximal substrings without spaces, called [13Xchunks[113X here,[133X
  
  [30X    [33X[0;6Ylet [22Xn[122X be the number of distinct chunks,[133X
  
  [30X    [33X[0;6Yif the number of chunks is not [22Xn^2[122X, report error,[133X
  
  [30X    [33X[0;6Yconstruct  the  multiplication  table by assigning numerical values [22X1[122X,
        [22Xdots[122X, [22Xn[122X to chunks, depending on their position among distinct chunks.[133X
  
  [33X[0;0YThe  following  examples clarify the algorithm and document its versatility.
  All examples are of the form [22XF+D⟹ T[122X, meaning that an input file containing [22XF[122X
  together with the deletion string [22XD[122X produce multiplication table [22XT[122X.[133X
  
  [33X[0;0Y[12XExample:[112X Data does not have to be arranged into an array of any kind.[133X
  
  
        [33X[1;6Y[24X[33X[0;0Y\begin{array}{cccc} 0&1&2&1\\ 2&0&2& \\ 0&1& & \end{array}\quad +
        \quad "" \quad \Longrightarrow\quad \begin{array}{ccc} 1&2&3\\ 2&3&1\\
        3&1&2 \end{array}[133X [124X[133X
  
  
  [33X[0;0Y[12XExample:[112X Chunks can be any strings.[133X
  
  
        [33X[1;6Y[24X[33X[0;0Y\begin{array}{cc} {\rm red}&{\rm green}\\ {\rm green}&{\rm red}\\
        \end{array}\quad + \quad "" \quad \Longrightarrow\quad
        \begin{array}{cc} 1& 2\\ 2& 1 \end{array}[133X [124X[133X
  
  
  [33X[0;0Y[12XExample:[112X  A  typical  table  produced  by  [5XGAP[105X  is easily parsed by deleting
  brackets and commas.[133X
  
  
        [33X[1;6Y[24X[33X[0;0Y[ [0, 1], [1, 0] ] \quad + \quad "[,]" \quad \Longrightarrow\quad
        \begin{array}{cc} 1& 2\\ 2& 1 \end{array}[133X [124X[133X
  
  
  [33X[0;0Y[12XExample:[112X  A  typical  TeX  table with rows separated by lines is also easily
  converted.  Note that we have to use [22Xbackslashbackslash[122X to ensure that every
  occurrence  of [22Xbackslash[122X is deleted, since [22Xbackslashbackslash[122X represents the
  character [22Xbackslash[122X in [5XGAP[105X[133X
  
  
        [33X[1;6Y[24X[33X[0;0Y\begin{array}{lll} x\&& y\&&\ z\backslash\backslash\cr y\&& z\&&\
        x\backslash\backslash\cr z\&& x\&&\ y \end{array} \quad + \quad
        "\backslash\backslash\&" \quad \Longrightarrow\quad \begin{array}{ccc}
        1&2&3\cr 2&3&1\cr 3&1&2 \end{array}[133X [124X[133X
  
  
  
  [1X4.5-1 [33X[0;0YQuasigroupFromFile and LoopFromFile[133X[101X
  
  [29X[2XQuasigroupFromFile[102X( [3Xfilename[103X, [3Xdel[103X ) [32X operation
  [29X[2XLoopFromFile[102X( [3Xfilename[103X, [3Xdel[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YThe  quasigroup (resp. loop) whose multiplication table data is in
            file  [3Xfilename[103X,  ignoring  the  characters contained in the string
            [3Xdel[103X.[133X
  
  
  [1X4.6 [33X[0;0YCreating Quasigroups and Loops From Sections[133X[101X
  
  [1X4.6-1 CayleyTableByPerms[101X
  
  [29X[2XCayleyTableByPerms[102X( [3XP[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YIf  [3XP[103X  is  a  set of [22Xn[122X permutations of an [22Xn[122X-element set [22XX[122X, returns
            Cayley table [22XC[122X such that [22XC[i][j] = X[j]^P[i][122X.[133X
  
  [33X[0;0YThe  cardinality  of the underlying set is determined by the moved points of
  the  first  permutation  in  [3XP[103X, unless the first permutation is the identity
  permutation, in which case the second permutation is used.[133X
  
  [33X[0;0YIn   particular,   if   [3XP[103X   is   the   left   section  of  a  quasigroup  [3XQ[103X,
  [10XCayleyTableByPerms([3XQ[103X[10X)[110X returns the multiplication table of [3XQ[103X.[133X
  
  
  [1X4.6-2 [33X[0;0YQuasigroupByLeftSection and LoopByLeftSection[133X[101X
  
  [29X[2XQuasigroupByLeftSection[102X( [3XP[103X ) [32X operation
  [29X[2XLoopByLeftSection[102X( [3XP[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YIf   [3XP[103X  is  a  set  of  permutations  corresponding  to  the  left
            translations   of   a   quasigroup   (resp.   loop),  returns  the
            corresponding quasigroup (resp. loop).[133X
  
  [33X[0;0YThe  order  of permutations in [3XP[103X is important in the quasigroup case, but it
  is  disregarded  in  the  loop  case,  since  then  the order of rows in the
  corresponding  multiplication  table  is  determined  by the presence of the
  neutral element.[133X
  
  
  [1X4.6-3 [33X[0;0YQuasigroupByRightSection and LoopByRightSection[133X[101X
  
  [29X[2XQuasigroupByRightSection[102X( [3XP[103X ) [32X operation
  [29X[2XLoopByRightSection[102X( [3XP[103X ) [32X operation
  
  [33X[0;0YThese    are    the   dual   operations   to   [10XQuasigroupByLeftSection[110X   and
  [10XLoopByLeftSection[110X.[133X
  
  [4X[32X  Example  [32X[104X
    [4X[25Xgap>[125X [27XS := Subloop( MoufangLoop( 12, 1 ), [ 3 ] );;
[127X[104X
    [4X[25Xgap>[125X [27Xls := LeftSection( S );
[127X[104X
    [4X[28X[ (), (1,3,5), (1,5,3) ]
[128X[104X
    [4X[25Xgap>[125X [27XCayleyTableByPerms( ls );
[127X[104X
    [4X[28X[ [ 1, 3, 5 ], [ 3, 5, 1 ], [ 5, 1, 3 ] ]
[128X[104X
    [4X[25Xgap>[125X [27XCayleyTable( LoopByLeftSection( ls ) );
[127X[104X
    [4X[28X[ [ 1, 2, 3 ], [ 2, 3, 1 ], [ 3, 1, 2 ] ]
[128X[104X
  [4X[32X[104X
  
  
  [1X4.7 [33X[0;0YCreating Quasigroups and Loops From Folders[133X[101X
  
  [33X[0;0YLet  [22XG[122X  be  a group, [22XH[122X a subgroup of [22XG[122X, and [22XT[122X a right transversal to [22XH[122X in [22XG[122X.
  Let  [22Xτ:G->  T[122X  be  defined  by [22Xx∈ Hτ(x)[122X. Then the operation [22X∘[122X defined on the
  right  cosets  [22XQ = {Ht|t∈ T}[122X by [22XHs∘ Ht = Hτ(st)[122X turns [22XQ[122X into a quasigroup if
  and only if [22XT[122X is a right transversal to all conjugates [22Xg^-1Hg[122X of [22XH[122X in [22XG[122X. (In
  fact, every quasigroup [22XQ[122X can be obtained in this way by letting [22XG= Mlt_ρ(Q)[122X,
  [22XH= Inn_ρ(Q)[122X and [22XT={R_x|x∈ Q}[122X.)[133X
  
  [33X[0;0YWe call the triple [22X(G,H,T)[122X a [13Xright quasigroup (or loop) folder[113X.[133X
  
  
  [1X4.7-1 [33X[0;0YQuasigroupByRightFolder and LoopByRightFolder[133X[101X
  
  [29X[2XQuasigroupByRightFolder[102X( [3XG[103X, [3XH[103X, [3XT[103X ) [32X operation
  [29X[2XLoopByRightFolder[102X( [3XG[103X, [3XH[103X, [3XT[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YThe quasigroup (resp. loop) from the right folder ([3XG[103X, [3XH[103X, [3XT[103X).[133X
  
  [33X[0;0Y[12XRemark:[112X  We  do  not support the dual operations for left sections since, by
  default, actions in [5XGAP[105X act on the right.[133X
  
  [33X[0;0YHere  is  a  simple  example in which [22XT[122X is actually the right section of the
  resulting loop.[133X
  
  [4X[32X  Example  [32X[104X
    [4X[25Xgap>[125X [27XT := [ (), (1,2)(3,4,5), (1,3,5)(2,4), (1,4,3)(2,5), (1,5,4)(2,3) ];;
[127X[104X
    [4X[25Xgap>[125X [27XG := Group( T );; H := Stabilizer( G, 1 );;
[127X[104X
    [4X[25Xgap>[125X [27XLoopByRightFolder( G, H, T );
[127X[104X
    [4X[28X<loop of order 5>
[128X[104X
  [4X[32X[104X
  
  
  [1X4.8 [33X[0;0YCreating Quasigroups and Loops By Nuclear Extensions[133X[101X
  
  [33X[0;0YLet  [22XK[122X, [22XF[122X be loops. Then a loop [22XQ[122X is an [13Xextension[113X of [22XK[122X by [22XF[122X if [22XK[122X is a normal
  subloop  of  [22XQ[122X such that [22XQ/K[122X is isomorphic to [22XF[122X. An extension [22XQ[122X of [22XK[122X by [22XF[122X is
  [13Xnuclear[113X if [22XK[122X is an abelian group and [22XKle N(Q)[122X.[133X
  
  [33X[0;0YA map [22Xθ:F× F-> K[122X is a [13Xcocycle[113X if [22Xθ(1,x) = θ(x,1) = 1[122X for every [22Xx∈ F[122X.[133X
  
  [33X[0;0YThe  following  theorem  holds for loops [22XQ[122X, [22XF[122X and an abelian group [22XK[122X: [22XQ[122X is a
  nuclear extension of [22XK[122X by [22XF[122X if and only if there is a cocycle [22Xθ:F× F-> K[122X and
  a  homomorphism [22Xφ:F-> Aut(Q)[122X such that [22XK× F[122X with multiplication [22X(a,x)(b,y) =
  (aφ_x(b)θ(x,y),xy)[122X is isomorphic to [22XQ[122X.[133X
  
  [1X4.8-1 NuclearExtension[101X
  
  [29X[2XNuclearExtension[102X( [3XQ[103X, [3XK[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YThe  data  necessary  to construct [3XQ[103X as a nuclear extension of the
            subloop  [3XK[103X  by [3XQ[103X[22X/[122X[3XK[103X, namely [22X[K, F, φ, θ][122X as above. Note that [3XK[103X must
            be a commutative subloop of the nucleus of [3XQ[103X.[133X
  
  [33X[0;0YIf  [22Xn=|F|[122X and [22Xm=|[122X[3XK[103X[22X|[122X, the cocycle [22Xθ[122X is returned as an [22Xn× n[122X array with entries
  in  [22X{1,dots,m}[122X,  and the homomorphism [22Xφ[122X is returned as a list of length [22Xn[122X of
  permutations of [22X{1,dots,m}[122X.[133X
  
  [1X4.8-2 LoopByExtension[101X
  
  [29X[2XLoopByExtension[102X( [3XK[103X, [3XF[103X, [3Xf[103X, [3Xt[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YThe  extension  of  an abelian group [3XK[103X by a loop [3XF[103X, using action [3Xf[103X
            and  cocycle  [3Xt[103X.  The arguments must be formatted as the output of
            [10XNuclearExtension[110X.[133X
  
  [4X[32X  Example  [32X[104X
    [4X[25Xgap>[125X [27XF := IntoLoop( Group( (1,2) ) );
[127X[104X
    [4X[28X<loop of order 2>
[128X[104X
    [4X[25Xgap>[125X [27XK := DirectProduct( F, F );;
[127X[104X
    [4X[25Xgap>[125X [27Xphi := [ (), (2,3) ];;
[127X[104X
    [4X[25Xgap>[125X [27Xtheta := [ [ 1, 1 ], [ 1, 3 ] ];;
[127X[104X
    [4X[25Xgap>[125X [27XLoopByExtension( K, F, phi, theta );
[127X[104X
    [4X[28X<loop of order 8>
[128X[104X
    [4X[25Xgap>[125X [27XIsAssociative( last );
[127X[104X
    [4X[28Xfalse
[128X[104X
  [4X[32X[104X
  
  
  [1X4.9 [33X[0;0YRandom Quasigroups and Loops[133X[101X
  
  [33X[0;0YAn  algorithm is said to select a latin square of order [22Xn[122X [13Xat random[113X if every
  latin  square  of  order  [22Xn[122X  is  returned  by  the  algorithm  with the same
  probability. Selecting a latin square at random is a nontrivial problem.[133X
  
  [33X[0;0YIn [JM96], Jacobson and Matthews defined a random walk on the space of latin
  squares  and so-called improper latin squares that visits every latin square
  with  the  same  probability.  The  diameter  of  the  space is no more than
  [22X4(n-1)^3[122X  in  the sense that no more than [22X4(n-1)^3[122X properly chosen steps are
  needed to travel from one latin square of order [22Xn[122X to another.[133X
  
  [33X[0;0YThe  Jacobson-Matthews  algorithm can be used to generate random quasigroups
  as  follows:  (i)  select  any  latin  square  of  order [22Xn[122X, for instance the
  canonical  multiplication table of the cyclic group of order [22Xn[122X, (ii) perform
  sufficiently many steps of the random walk, stopping at a proper or improper
  latin  square, (iii) if necessary, perform a few more steps to end up with a
  proper  latin square. Upon normalizing the resulting latin square, we obtain
  a random loop of order [22Xn[122X.[133X
  
  [33X[0;0YBy  the  above  result,  it suffices to use about [22Xn^3[122X steps to arrive at any
  latin  square  of  order [22Xn[122X from the initial latin square. In fact, a smaller
  number of steps is probably sufficient.[133X
  
  
  [1X4.9-1 [33X[0;0YRandomQuasigroup and RandomLoop[133X[101X
  
  [29X[2XRandomQuasigroup[102X( [3Xn[103X[, [3Xiter[103X] ) [32X operation
  [29X[2XRandomLoop[102X( [3Xn[103X[, [3Xiter[103X] ) [32X operation
  [6XReturns:[106X  [33X[0;10YA   random   quasigroup   (resp.   loop)  of  order  [3Xn[103X  using  the
            Jacobson-Matthews  algorithm.  If  the  optional  argument [3Xiter[103X is
            omitted, [3Xn[103X[22X^3[122X steps are used. Otherwise [3Xiter[103X steps are used.[133X
  
  [33X[0;0YIf  [3Xiter[103X  is small, the Cayley table of the returned quasigroup (resp. loop)
  will be close to the canonical Cayley table of the cyclic group of order [3Xn[103X.[133X
  
  [1X4.9-2 RandomNilpotentLoop[101X
  
  [29X[2XRandomNilpotentLoop[102X( [3Xlst[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YA  random  nilpotent  loop  as  follows  (see Section [14X6.9[114X for more
            information  on  nilpotency):  [3Xlst[103X  must  be  a  list  of positive
            integers  and/or  finite  abelian groups. If [10X[3Xlst[103X[10X=[a1][110X and [10Xa1[110X is an
            integer,  a  random abelian group of order [10Xa1[110X is returned, else [10Xa1[110X
            is   an   abelian  group  and  [10XAsLoop(a1)[110X  is  returned.  If  [10X[3Xlst[103X[10X=
            [a1,...,am][110X,      a      random      central      extension     of
            [10XRandomNilpotentLoop([a1])[110X  by  [10XRandomNilpotentLoop([a2,...,am])[110X is
            returned.[133X
  
  [33X[0;0YTo  determine  the nilpotency class [22Xc[122X of the resulting loop, assume that [3Xlst[103X
  has  length  at  least 2, contains only integers bigger than 1, and let [22Xm[122X be
  the  last  entry  of  [3Xlst[103X.  If [22Xm>2[122X then [22Xc[122X is equal to [10XLength([3Xlst[103X[10X)[110X, else [22Xc[122X is
  equal to [10XLength([3Xlst[103X[10X)-1[110X.[133X
  
  
  [1X4.10 [33X[0;0YConversions[133X[101X
  
  [33X[0;0Y[5XLOOPS[105X  contains  methods that convert between magmas, quasigroups, loops and
  groups,  provided  such  conversions  are  possible.  Each of the conversion
  methods [10XIntoQuasigroup[110X, [10XIntoLoop[110X and [10XIntoGroup[110X returns [10Xfail[110X if the requested
  conversion is not possible.[133X
  
  [33X[0;0Y[12XRemark:[112X  Up to version 2.0.0 of [5XLOOPS[105X, we supported [10XAsQuasigroup[110X, [10XAsLoop[110X and
  [10XAsGroup[110X in place of [10XIntoQuasigroup[110X, [10XIntoLoop[110X and [10XIntoGroup[110X, respectively. We
  have  changed the terminology starting with version 2.1.0 in order to comply
  with  [5XGAP[105X  naming rules for [10XAsSomething[110X, as explained in Chapter [14X3[114X. Finally,
  the  method  [10XAsGroup[110X is a core method of [5XGAP[105X that returns an fp group if its
  argument is an associative loop.[133X
  
  [1X4.10-1 IntoQuasigroup[101X
  
  [29X[2XIntoQuasigroup[102X( [3XM[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YIf  [3XM[103X  is  a  declared  magma that happens to be a quasigroup, the
            corresponding  quasigroup is returned. If [3XM[103X is already declared as
            a quasigroup, [3XM[103X is returned.[133X
  
  [1X4.10-2 PrincipalLoopIsotope[101X
  
  [29X[2XPrincipalLoopIsotope[102X( [3XM[103X, [3Xf[103X, [3Xg[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YAn  isomorphic  copy  of  the  principal  isotope  [22X([122X[3XM[103X,[22X∘)[122X  via  the
            transposition  [22X(1[122X,[3Xf[103X[22X⋅[122X[3Xg[103X[22X)[122X. An isomorphic copy is returned rather than
            [22X([122X[3XM[103X,[22X∘)[122X  because  in  [5XLOOPS[105X  all  loops have to have neutral element
            labeled as [22X1[122X.[133X
  
  [33X[0;0YGiven  a  quasigroup  [22XM[122X  and  two  of  its elements [22Xf[122X, [22Xg[122X, the principal loop
  isotope  [22Xx∘  y  =  R_g^-1(x)⋅ L_f^-1(y)[122X turns [22X(M,∘)[122X into a loop with neutral
  element [22Xf⋅ g[122X (see Section [14X2.6[114X).[133X
  
  [1X4.10-3 IntoLoop[101X
  
  [29X[2XIntoLoop[102X( [3XM[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YIf  [3XM[103X is a declared magma that happens to be a quasigroup (but not
            necessarily  a  loop!),  a  loop  is  returned as follows: If [3XM[103X is
            already  declared as a loop, [3XM[103X is returned. Else, if [3XM[103X possesses a
            neutral  element  [22Xe[122X  and  if  [22Xf[122X is the first element of [3XM[103X, then an
            isomorphic copy of [3XM[103X via the transposition [22X(e,f)[122X is returned. If [3XM[103X
            does  not  posses  a neutral element, [10XPrincipalLoopIsotope([3XM[103X[10X, [3XM.1[103X[10X,
            [3XM.1[103X[10X)[110X is returned.[133X
  
  [33X[0;0Y[12XRemark:[112X  One could obtain a loop from a declared magma [3XM[103X in yet another way,
  by  normalizing  the  Cayley  table of [3XM[103X. The three approaches can result in
  nonisomorphic loops in general.[133X
  
  [1X4.10-4 IntoGroup[101X
  
  [29X[2XIntoGroup[102X( [3XM[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YIf  [3XM[103X  is  a  declared  magma  that  happens  to  be  a group, the
            corresponding  group  is  returned  as  follows:  If  [3XM[103X is already
            declared     as     a     group,     [3XM[103X     is    returned,    else
            [10XRightMultiplicationGroup(IntoLoop([3XM[103X[10X))[110X  is  returned,  which  is  a
            permutation group isomorphic to [3XM[103X.[133X
  
  
  [1X4.11 [33X[0;0YProducts of Quasigroups and Loops[133X[101X
  
  [1X4.11-1 DirectProduct[101X
  
  [29X[2XDirectProduct[102X( [3XQ1[103X, [3X...[103X, [3XQn[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YIf  each  [3XQi[103X  is  either a declared quasigroup, declared loop or a
            declared group, the direct product of [3XQ1[103X, [22Xdots[122X, [3XQn[103X is returned. If
            every  [3XQi[103X is a declared group, a group is returned; if every [3XQi[103X is
            a  declared  loop,  a  loop is returned; otherwise a quasigroup is
            returned.[133X
  
  
  [1X4.12 [33X[0;0YOpposite Quasigroups and Loops[133X[101X
  
  [33X[0;0YWhen  [22XQ[122X  is a quasigroup with multiplication [22X⋅[122X, the [13Xopposite quasigroup[113X of [22XQ[122X
  is  a quasigroup with the same underlying set as [22XQ[122X and with multiplication [22X*[122X
  defined by [22Xx*y=y⋅ x[122X.[133X
  
  
  [1X4.12-1 [33X[0;0YOpposite, OppositeQuasigroup and OppositeLoop[133X[101X
  
  [29X[2XOpposite[102X( [3XQ[103X ) [32X attribute
  [29X[2XOppositeQuasigroup[102X( [3XQ[103X ) [32X operation
  [29X[2XOppositeLoop[102X( [3XQ[103X ) [32X operation
  [6XReturns:[106X  [33X[0;10YThe  opposite  of  the  quasigroup  (resp.  loop)  [3XQ[103X. Note that if
            [10XOppositeQuasigroup([3XQ[103X[10X)[110X  or  [10XOppositeLoop([3XQ[103X[10X)[110X  are  called,  then the
            returned quasigroup or loop is not stored as an attribute of [3XQ[103X.[133X
  
