... have something like X --> Z, you are being told that ... other. If X is In, Z is Out and vice versa ... ), AND if both X and Z cannot be In (not both ... option In and the X/Z option Out. The reason JY ...
... IF it does, then Z. So, in Z & X ---> Y ... to satisfy this condition first. Z is a necessary condition, so ... sufficient condition in which case Z is free to go either ... is not strictly necessary from Z & X.
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(/X or Y) --->Z this is equivalent to:
/(/X or Y) or Z this can be simplified to ... {(X and /Y) or Z} gives us two possibilities:
/(X and /Y)--> Z