שינויים

<)math>\left |p(A)\Delta p(B) \right |= \left |(A/B)\cup (B/A) \right |=\left |p(A)/p(B ) \right |+\left | p(B)/p(A ) \right |-\left | (p(B)/p(A))\cap (p(A)/p(B)) \right |=\left | p(A \right |-\left | p(A\cap B ) \right |+\left | p(B ) \right |-\left | p(A\cap B ) \right |=2^{n}+2^{m}-2\cdot 2^{k}=2^{n}+2^{m}-2^{k+1}</math>