JSC
2010
13 years 7 months ago
2010
For a field k with an automorphism and a derivation , we introduce the notion of liouvillian solutions of linear difference-differential systems {(Y ) = AY, (Y ) = BY } over k an...
IJAC
2010
13 years 11 months ago
2010
We show that the following problems are decidable in rank 2 free groups: does a given finitely generated subgroup H contain primitive elements? and does H meet the automorphic or...
MOC
2002
14 years 12 days ago
2002
There are 50,024 Kirkman triple systems of order 21 admitting an automorphism of order 2. There are 13,280 Kirkman triple systems of order 21 admitting an automorphism of order 3. ...
APAL
1999
14 years 13 days ago
1999
The present paper investigates the groups of automorphisms for some lattices of modal logics. The main results are the following. The lattice of normal extensions of S4.3, NExt S4....
CPC
2000
14 years 17 days ago
2000
We prove that if an involution is an automorphism of a connected binary matroid M, then there is a hyperplane of M that is invariant under . We also consider extensions of this re...
COMBINATORICS
2006
14 years 23 days ago
2006
A set of vertices S is a determining set for a graph G if every automorphism of G is uniquely determined by its action on S. The determining number of a graph is the size of a sma...
CC
2006
Springer
14 years 24 days ago
2006
Springer
Abstract. We study the complexity of the isomorphism and automorphism problems for finite rings. We show that both integer factorization and graph isomorphism reduce to the problem...
DM
2010
14 years 25 days ago
2010
Abstract: Duality and chirality are examples of operations of order 2 on hypermaps. James showed that the groups of all operations on hypermaps and on oriented hypermaps can be ide...