 In TS, § 155, no. 26, he introduces the concept of exact deducibility: \(M\) is exactly deducible from \(A, B, C, \ldots\), we read there, just in case \(M\) is deducible from \(A, B, C, \ldots\) but no relation of deducibility holds if any of the premises, or any of their parts, is omitted. A deduction that is not exact is called redundant. In the shorter version of his logic (Bolzano 2004a: 54), the stipulation about omitting parts is dropped. This was probably wise, as the additional condition seems to have some unwelcome consequences (cf. Rusnock and Šebestík, 2019, 312–3).