Short presentations for alternating and symmetric groups

Short presentations for alternating and symmetric groups

We derive new families of presentations (by generators and relations) for the alternating and symmetric groups of finite degree n. These include presentations of length that are linear in log n, and 2-generator presentations with a bounded number of relations independent of n.

Short Presentations for Finite Groups

We conjecture that every nite group G has a short presentation (in terms of generators and relations) in the sense that the total length of the relations is (log jGj) O(1). We show that it suuces to prove this conjecture for simple groups. Motivated by applications in computational complexity theory, we conjecture that for nite simple groups, such a short presentation is computable in polynomia...

Regular polytopes with symmetric and alternating groups

Short presentations for three-dimensional unitary groups

We give a presentation of length O ( log2 |G| ) for the groups G∼= PSU3(q). This result has applications in recent algorithms to compute the structure of permutation groups and matrix groups.

On Alternating and Symmetric Groups as Galois Groups

Fix an integer n = 3. We show that the alternating group An appears as Galois group over any Hilbertian field of characteristic different from 2. In characteristic 2, we prove the same when n is odd. We show that any quadratic extension of Hilbertian fields of characteristic different from 2 can be embedded in an Sn–extension (i.e. a Galois extension with the symmetric group Sn as Galois group)...