BT Šab 97b(11) :דאי ס׳ד ר׳ יהודה חדא הוא דמחייב מכלל דרבנן פטרי לגמרי‏ : if you think that PN holds him liable for one (sacrifice), the inference is that the rabbis exempt him completely
See the entire entry for mkll conj. by inference