 That is, just as ideas \(A, B, C, \ldots\) are said to be compatible iff at least one object stands under each of \(A, B, C, \ldots\), so too we can say that propositions \(A, B, C, \ldots\) are compatible with respect to variable ideas \(i, j, k, \ldots\) iff there is at least one collection of ideas \(i’, j’, k’, \ldots\) which are verifying ideas for each of \(A, B, C, \ldots\). Equivalently, \(A, B, C, \ldots\) are compatible relative to \(i, j, k, \ldots\) iff the ideas [verifying ideas for \(A\) relative to \(i, j, k, \ldots\)], [verifying ideas for \(B\) relative to \(i, j, k, \ldots\)], [verifying ideas for \(C\) relative to \(i, j, k, \ldots\)] are compatible in the previously defined sense; otherwise, they are said to be incompatible.