Based on fieldwork in an upper-secondary school Sweden, this paper centers Swedish as two school-subjects: (SWE) and a second language (SSL), taught one class. Adhering to separate curricula, by SWE SSL teachers respectively, they are often implemented physically separated subjects. By contrast, explores three different learning spaces relation everyday negotiations of belonging participation a...

We describe a criterion for real or complex hyperbolic lattice to admit residually finite rational solvable (RFRS) tower that consists entirely of congruence subgroups. use this show certain Bianchi groups PSL 2 (

The study of representation requires being able to measure representation. The concept to be measured, in the abstract, is the distance or “congruence” between legislators and their constituents, but data limitations often preclude measuring congruence directly. A popular alternative is to regress legislator roll call votes on a proxy for constituent preferences, with the coefficient labeled “r...

In program algebra, an algebraic theory of single-pass instruction sequences, three congruences on instruction sequences are paid attention to: instruction sequence congruence, structural congruence, and behavioural congruence. Sound and complete axiom systems for the first two congruences were already given in early papers on program algebra. The current paper is the first one that is concerne...

The aim of this paper is to further develop the congruence theory on lattice implication algebras. Firstly, we introduce the notions of vague similarity relations based on vague relations and vague congruence relations. Secondly, the equivalent characterizations of vague congruence relations are investigated. Thirdly, the relation between the set of vague filters and the set of vague congruence...

We study the problem of characterizing contextual equivalence in higher-orderlanguages with passivation. To overcome the difficulties arising in the proofof congruence of candidate bisimilarities, we introduce a new form of labelledtransition semantics together with its associated notion of bisimulation, whichwe call complementary semantics. Complementary semantics allows to...

Introduction In the theory of groups, the important concepts of Abelian group, solvable group, nilpotent group, the center of a group and centraliz-ers, are all defined from the binary operation [x, y] = x −1 y −1 xy. Each of these notions, except centralizers of elements, may also be defined in terms of the commutator of normal subgroups. The commutator [M, N] (where M and N are normal subgrou...

Prefix iteration is a variation on the original binary version of the Kleene star operation P Q, obtained by restricting the first argument to be an atomic action. The interaction of prefix iteration with silent steps is studied in the setting of Milner’s basic CCS. Complete equational axiomatizations are given for four notions of behavioural congruence over basic CCS with prefix iteration, viz...