Bilateralism,Trilateralism, Multilateralism and Poly-Sequents

The paper introduces the formula structure of poly-sequents, allowing the expression of poly-positions: positions with any number of stances, of which bilateralism and trilateralism are special cases. The paper also puts forward the view that s-coherence (strong coherence) of such poly-positions can be defined inferentially, without appealing to their validity under interpretations of the object language.