are logically compatible if, and only if, the union between them <math>\Im\cup\{\delta_1,\delta_2.....\delta_n\}</math> is coherent
are logically compatible if, and only if, the union between them ℑ ∪ { δ 1 , δ 2 . . . . . δ n } {\displaystyle \Im \cup \{\delta _{1},\delta _{2}.....\delta _{n}\}} is coherent