To see why the ''Dispersion Rule'' holds, look at it this way: If ''x'' is true, then the presence of ''x'' makes no difference on either side of the equation, but if ''x'' is false, then both sides of the equation are false.
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To see why the ''Dispersion Rule'' holds, look at it this way: If <math>x\!</math> is true, then the presence of <math>x\!</math> makes no difference on either side of the equation, but if <math>x\!</math> is false, then both sides of the equation are false.
Here is a proof sketch for the ''Case Analysis-Synthesis Theorem'' (CAST):
Here is a proof sketch for the ''Case Analysis-Synthesis Theorem'' (CAST):