Common conventions to indicate a morphophonemic rather than phonemic representation include double slashes (⫽  ⫽) (as above, implying that the transcription is 'more phonemic than simply phonemic'). This is the only convention consistent with the IPA. Other conventions include pipes (|  |), double pipes (‖  ‖) and braces ({  }). Braces, from a convention in set theory, tend to be used when the phonemes are all listed, as in {s, z, ᵻz} and {t, d, ᵻd} for the English plural and past-tense morphemes ⫽z⫽ and ⫽d⫽ above.