A @P04740@ in which a cyclic @M04017@ yields a @M04018@ which is acyclic or contains fewer cycles than the @M04017@.
If the @M04017@ is polycyclic, the opening of a single ring is sufficient to classify the reaction as ring-opening @P04740@.
PAC, 1996, 68, 2287. (Glossary of basic terms in polymer science (IUPAC Recommendations 1996)) on page 2308 [Terms] [Paper]