4 ms·
I would be interested to see this written formally (at least the premise, if not also the steps) -- is there a Boolean notation for this sort of thing?
by detcader 12y ago
I would be interested to see this written formally (at least the premise, if not also the steps) -- is there a Boolean notation for this sort of thing?
- contravariant 12y agoPerhaps a combination of boolean logic and set theory? For instance let X be the set of possible dates and let m, d, be functions which, respectively, return the month and the day of any date in X. Now the three statements can be translated to the following logical statements (this isn't necessarily a good thing to do, but you can): P(B) = #m^-1(m(B)) > 1 ∧ ∀x∈m^-1(m(B)) : #d^-1(d(x)) > 1 Q(B) = ∃!x∈X: d(x)=d(B) ∧ P(x) R(B) = ∃!x∈X: m(x)=m(B) ∧ Q(x) your task is then to find a birthday B in X such that P(B), Q(B), and R(B) hold. Or equivalently find the unique element of {x∈X : P(x)∧Q(x)∧R(x)}. Edit: Still not 100% sure if P(B) is correct.