Package-level declarations

Thrown when :solve-problog's internal clause-mapping logic -- the step that rewrites a ProbLog theory (annotated disjunctions, evidence, plain Prolog clauses) into a Prolog-compliant one carrying explanation terms -- receives a it.unibo.tuprolog.core.Clause it cannot handle, e.g. one of an unexpected subtype for the mapper being applied, or malformed with respect to the mapper's expectations (a badly-formed annotated disjunction, an evidence predicate with the wrong arity or argument type, and similar cases). It generally signals a bug in the mapping pipeline itself, or a theory that superficially matched a mapper's predicate but violates one of its structural preconditions.