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open-psa / mef

The Open-PSA Model Exchange Format
https://open-psa.github.io/mef
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Limit XOR and IFF to two arguments #59

Open rakhimov opened 6 years ago

rakhimov commented 6 years ago

Currently, XOR and IFF are specified as n-ary connectives. Besides being rarely used/needed, these connectives are not intuitive in their associative, n-ary forms. For example, a naive user may confuse XOR with natural 'either .. or', which doesn't hold with more than 2 args; it is rather 'odd' (pun intended :)).

I think those FTA tools that do support these gates limit the number of arguments to 2 (e.g., graphically). It would be unreasonable to require generality without a practical need.

cfolleau commented 6 years ago

I agree totally. Never seen the use of un XOR with more than 2 args. Moreover there to 2 ways defined it (either one and only one, or parity)