Investigations into the structure of the congruence lattices of pseudocomplemented semilattices (PCS's) were initiated in [10]. In this paper a we characterize the class of congruence-semimodular PCS's (i.e. PCS's ...

An l-hemi-implicative semilattice is an algebra A=(A,∧,→,1) such that (A,∧,1) is a semilattice with a greatest element 1 and satisfies: (1) for every a,b,c∈A , a≤b→c implies a∧b≤c and (2) a→a=1 . An ...

For one-dimensional systems of conservation laws admitting two additional conservation laws, we assign a ruled hypersurface of codimension two in projective space. We call two such systems dual if the corresponding ruled ...

Ao analisar a Base Nacional Comum Curricular (BNCC), observa-se que devem ser enfatizadas as tarefas que analisam e produzem transformações e ampliações ou reduções de figuras geométricas planas, identificando seus elementos ...

This study provides a narrative of the perspectives and beliefs of a group of teachers and adolescent students regarding their roles and relationships, with specific reference to the classroom. Data were collected through ...