We revisit known transformations of conditional rewrite systems to unconditional ones in a systematic way. We present a unified framework for describing and classifying such transformations, discuss the major problems arising, provide simplified (old) and new counterexamples to certain (desirable) properties of specific transformations, and finally present a new transformation which has some advantages as compared to a quite recent approach, namely the one of [1]. 1 In this abstract, due to lack of space we focus on the latter contribution, after briefly discussing major general issues with such transformation approaches. Conditional term rewrite systems (CTRSs) and conditional equational specifications are very important in algebraic specification, prototyping, implementation and programming. They naturally occur in most practical applications. Yet, compared to unconditional term rewrite systems (TRSs), CTRSs are much more complicated, both in theory (especially concerning criteria and proof techniques for major properties of such systems like confluence and termination) and practice (implementing conditional rewriting in a clever way is far from being

We revisit (un)soundness of transformations of conditional into unconditional rewrite systems. The focus here is on so-called unravelings, the most simple and natural kind of such transformations, for the class of normal conditional systems without extra variables. By a systematic and thorough study of existing counterexamples and of the potential sources of unsoundness we obtain several new positive and negative results. In particular, we prove the following new results: Confluence, non-erasingness and weak left-linearity (of a given conditional system) each guarantee soundness of the unraveled version w.r.t. the original one. The latter result substantially extends the only known sufficient criterion for soundness, namely left-linearity. Furthermore, by means of counterexamples we refute various other tempting conjectures about sufficient conditions for soundness.