OI常用数学公式大全

莫比乌斯反演

[n=1]=∑d∣nμ(d)[n=1] = \sum_{d|n}\mu(d)

G(n)=∑d∣nF(d)⇔F(n)=∑d∣nμ(nd)G(d)G(n) = \sum_{d|n}F(d) \Leftrightarrow F(n) = \sum_{d|n}\mu(\frac{n}{d})G(d)

二项式反演

G(n)=∑i=0n(ni)(−1)iF(i)⇔F(n)=∑i=0n(ni)(−1)iG(i)G(n) = \sum_{i=0}^{n}\tbinom{n}{i}(-1)^{i}F(i) \Leftrightarrow F(n) = \sum_{i=0}^{n}\tbinom{n}{i}(-1)^{i}G(i)

G(n)=∑i=0n(ni)F(i)⇔F(n)=∑i=0n(ni)(−1)n−iG(i)G(n) = \sum_{i=0}^{n}\tbinom{n}{i}F(i) \Leftrightarrow F(n) = \sum_{i=0}^{n}\tbinom{n}{i}(-1)^{n-i}G(i)

G(n)=∑i=n(in)F(i)⇔F(n)=∑i=n(in)(−1)i−nG(i)G(n) = \sum_{i=n}\tbinom{i}{n}F(i) \Leftrightarrow F(n) = \sum_{i=n}\tbinom{i}{n}(-1)^{i-n}G(i)

Min-Max反演

max⁡(S)=∑T⊆S(−1)∣T∣+1min⁡(T)\max(S) = \sum_{T \subseteq S} (-1)^{|T|+1}\min(T)

min⁡(S)=∑T⊆S(−1)∣T∣+1max⁡(T)\min(S) = \sum_{T \subseteq S} (-1)^{|T|+1}\max(T)

Kth反演

kthmax(S)=∑T⊆S(−1)∣T∣−k(∣T∣−1k−1)min⁡(T)kthmax(S) = \sum_{T\subseteq S} (-1) ^{|T|-k}\tbinom{|T|-1}{k - 1}\min(T)

kthmin(S)=∑T⊆S(−1)∣T∣−k(∣T∣−1k−1)max⁡(T)kthmin(S) = \sum_{T\subseteq S} (-1) ^{|T|-k}\tbinom{|T|-1}{k - 1}\max(T)

斯特林反演

F(n)=∑i=0n{ni}G(i)⇔G(n)=∑i=0n(−1)n−i[ni]F(i)F(n) = \sum_{i=0}^{n} \begin{Bmatrix}n\\i\end{Bmatrix} G(i) \Leftrightarrow G(n) = \sum_{i=0}^{n} (-1)^{n-i}\begin{bmatrix}n\\i\end{bmatrix}F(i)

F(n)=∑i=0n(−1)n−i{ni}G(i)⇔G(n)=∑i=0n[ni]F(i)F(n) = \sum_{i=0}^{n} (-1)^{n-i}\begin{Bmatrix}n\\i\end{Bmatrix} G(i) \Leftrightarrow G(n) = \sum_{i=0}^{n} \begin{bmatrix}n\\i\end{bmatrix}F(i)

F(n)=∑i=n{in}G(i)⇔G(n)=∑i=n(−1)i−n[in]F(i)F(n) = \sum_{i=n}^{} \begin{Bmatrix}i\\n\end{Bmatrix} G(i) \Leftrightarrow G(n) = \sum_{i=n}^{} (-1)^{i-n}\begin{bmatrix}i\\n\end{bmatrix}F(i)

F(n)=∑i=n(−1)i−n{in}G(i)⇔G(n)=∑i=n[in]F(i)F(n) = \sum_{i=n}^{}(-1)^{i-n} \begin{Bmatrix}i\\n\end{Bmatrix} G(i) \Leftrightarrow G(n) = \sum_{i=n}^{} \begin{bmatrix}i\\n\end{bmatrix}F(i)