A Dichotomy for Some Elementarily Generated Modal Logics

作者：Kikot Stanislav^*

来源：Studia Logica, 2015, 103(5): 1063-1093.

DOI：10.1007/s11225-015-9611-6

• Canonical axiomatisation
• Generalised Sahlqvist theorem
• Modal definability
• Finite axiomatisability

In this paper we consider the normal modal logics of elementary classes defined by first-order formulas of the form . We prove that many properties of these logics, such as finite axiomatisability, elementarity, axiomatisability by a set of canonical formulas or by a single generalised Sahlqvist formula, together with modal definability of the initial formula, either simultaneously hold or simultaneously do not hold.

• 出版日期2015-10