COMPUTATIONAL PROBLEMS IN ABSTRACT ALGEBRA.

COMPUTATIONAL PROBLEMS IN ABSTRACT ALGEBRA. COMPUTATIONAL PROBLEMS IN ABSTRACT ALGEBRA.

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54 H. Jiirgensen Calculation with elements of a finite group 55 It is important here that the multiplication algorithm is defined for seminormed words as left factors. For computing jail (i = l(l)n) M* is used. 4.6. M developedfrom M*. What proved to be most time-consuming% that with an AG-system given the number of steps to be taken for norming the word aia%&sj-l I 3 1” .a> will in general increase rather fast, when Sj is increased. As a remedy further normed words h, = [ai, a:] (1 e i -= j 5 n; 2 == k-= vi> are introduced, if there exist i and j (1 e i-=j=sn) such that vj + 2 and gii + e. For computing these normed words M* is used. In M* norming a,u,dra$:;. . .a? for i-=j and 6j>l is based on the equation aiais,& 8,-l 6,-I a1‘I = ajaigija, . . . C7j-l . . . a$. The subroutines P(i, j, k) of M* for i

56 H. Jiirgensen Calculation with elements of a finite group 57 of commutators by which it may be defined.? Such systems (P-systems) exist as defining ones for every finite soluble group and even for some finite groups which are not soluble. If opj) = 1 (i = l(l)j- 1; j = 2(l)n), i.e. the group is soluble, there exists a well-defined finite multiplication algorithm. (d) Some non-soluble finite groups may be calculated, when an “extended P-system” is given. As far as P-systems are concerned, the extended ones seem to be the “weakest” with a well-defined finite multiplication algorithm existing. A new version of the programming programme, which is just being written, will allow the input data, i.e. the defining system, to be a mixture of AG-, K-, P-, and extended P-systems, and the words to be not necessarily normed ones. REFERENCES 1. W. LINDENBERG: ijber eine Darstelhmg von Gruppenelementen in digitalen Rechenautomaten. Num. Math. 4 (1962), 151-153. 2. W. LINDENBERG: Die Struktur eines Obersetzungsprogrammes zur Multiplikation von Gruppenelementen in digitalen Rechenautomaten. Mitt. Rh- W. Inst. Znstr. Math. Bonn 2 (1963), l-38. 3. J. NEUB~~SER: Bestimmung der Untergruppenverblnde endlicher p-Gruppen auf einer programmgesteuerten elektronischen Dualmaschine. Num. Math. 3 (1961), 271-278. 4. See the papers by C. BROTT, R. BULOW, K. FERBER, V. FELSCH and J. NEUB~SER in these Proceedings. t at = ai= ai = aa = e, ala, = a,a,, ala3 = a3a2, ala, = afa,a,al, a,u, = a,a,a,, a2a4 = a,4a,, u3a4 = a4a$a2u1.

56 H. Jiirgensen Calculation with elements of a finite group 57<br />

of commutators by which it may be defined.? Such systems (P-systems)<br />

exist as defining ones for every finite soluble group and even for some finite<br />

groups which are not soluble. If opj) = 1 (i = l(l)j- 1; j = 2(l)n), i.e. the<br />

group is soluble, there exists a well-defined finite multiplication algorithm.<br />

(d) Some non-soluble finite groups may be calculated, when an “extended<br />

P-system” is given. As far as P-systems are concerned, the extended ones<br />

seem to be the “weakest” with a well-defined finite multiplication algorithm<br />

existing.<br />

A new version of the programming programme, which is just being written,<br />

will allow the input data, i.e. the defining system, to be a mixture of<br />

AG-, K-, P-, and extended P-systems, and the words to be not necessarily<br />

normed ones.<br />

REFERENCES<br />

1. W. L<strong>IN</strong>DENBERG: ijber eine Darstelhmg von Gruppenelementen in digitalen Rechenautomaten.<br />

Num. Math. 4 (1962), 151-153.<br />

2. W. L<strong>IN</strong>DENBERG: Die Struktur eines Obersetzungsprogrammes zur Multiplikation<br />

von Gruppenelementen in digitalen Rechenautomaten. Mitt. Rh- W. Inst. Znstr. Math.<br />

Bonn 2 (1963), l-38.<br />

3. J. NEUB~~SER: Bestimmung der Untergruppenverblnde endlicher p-Gruppen auf einer<br />

programmgesteuerten elektronischen Dualmaschine. Num. Math. 3 (1961), 271-278.<br />

4. See the papers by C. BROTT, R. BULOW, K. FERBER, V. FELSCH and J. NEUB~SER<br />

in these Proceedings.<br />

t at = ai= ai = aa = e, ala, = a,a,, ala3 = a3a2, ala, = afa,a,al, a,u, = a,a,a,,<br />

a2a4 = a,4a,, u3a4 = a4a$a2u1.

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