/* black box recognition procedure for Fi23 */ StandardGeneratorsFi23 := function (G : Projective := false, Limit := 100) Fct := Projective select ProjectiveOrder else Order; P := RandomProcessWithWords (G); g, w := ElementOfOrder (P, {20,28}, Limit: Fct := Fct); if Type (g) eq BoolElt then return false, _; end if; o := Fct (g); x := g^(o div 2); xw := w^(o div 2); nmr0 := Limit; repeat nmr0 -:= 1; b, bw := ElementOfOrder (P, 3, Limit: Fct := Fct); if Type (b) eq BoolElt then return false, _; end if; nmr := Limit; repeat nmr -:= 1; c, cw := Random (P); a := x^c; until Fct (a * b) eq 28 or nmr eq 0; aw := xw^cw; until nmr ne 0 or nmr0 eq 0; if nmr0 eq 0 then return false, _; end if; if not PresentationFi23 (G: UserGenerators := [a, b], Projective := Projective) then return false, _; end if; return [a, b], [aw, bw]; end function;