Independence friendly logic (IF logic, IF first-order logic) is an extension of first-order logic. In
it, more quantifier dependencies and independencies can be expressed than in first-order …

Typical applications of Hintikka's game-theoretical semantics (GTS) give rise to semantic
attributes—truth, falsity—expressible in the Σ 1 1-fragment of second-order logic. Actually a …

It is well-known that Independence Friendly (IF) logic is equivalent to existential second-
order logic (Σ 1 1) and, therefore, is not closed under classical negation. The Boolean …