Basic concepts

reference.reference,reference,reference.reference,reference,reference.reference,reference1,reference OI reference.reference,reference.

reference,reference:

reference,reference.reference,reference、reference、reference.

reference

reference.

reference

reference GG reference,reference ⋅:G×G→G\cdot:G\times G\rightarrow G,reference,reference (G,⋅)(G,\cdot) reference reference(group):

  1. reference(associative property):reference a,b,c∈Ga,b,c\in G,reference a⋅(b⋅c)=(a⋅b)⋅ca\cdot(b\cdot c)=(a\cdot b)\cdot c;
  2. reference:reference e∈Ge\in G,reference a∈Ga\in G,reference a⋅e=e⋅a=aa\cdot e = e\cdot a = a.reference,ee reference GG reference reference(identity element),reference;
  3. reference:reference a∈Ga\in G,reference b∈Gb\in G reference a⋅b=b⋅a=ea\cdot b=b\cdot a=e.reference,bb reference aa reference reference(inverse element).
reference

reference,reference a,b∈Ga,b\in G,reference a⋅b∈Ga\cdot b\in G.reference.

reference

reference (G,⋅)(G,\cdot),reference:

  1. reference {gi}i=1k⊆G\{g_i\}_{i=1}^k\subseteq G,reference g1⋅g2⋅⋯⋅gkg_1\cdot g_2\cdot\cdots\cdot g_k reference;
  2. reference ee reference;
  3. reference a∈Ga\in G,reference a−1a^{-1} reference;
  4. reference(cancellation law):reference a,b,c∈Ga,b,c\in G,reference a⋅c=b⋅ca\cdot c=b\cdot c reference c⋅a=c⋅bc\cdot a=c\cdot b,reference a=ba=b.

reference.reference,reference.reference.

reference
  • reference(symmetric group):reference MM reference reference,reference MM reference MM reference,reference SMS_M.reference,reference(reference).reference MM reference,reference nn,reference SnS_n,reference nn reference.
  • reference(symmetry group):reference,reference.reference.reference reference.
  • reference:reference Z\mathbf Z reference ++ reference (Z,+)(\mathbf Z,+).reference 00,reference.
  • reference nn reference(multiplicative group of integers modulo nn):reference nn,reference nn reference reference,reference ((Z/nZ)×,×)((\mathbf Z/n\mathbf Z)^\times,\times).reference 1ˉ\bar 1,reference nn reference reference(reference),reference reference reference.reference reference nn reference.
  • reference(general linear group):reference FF reference nn reference GLn(F)GL_n(F).reference,reference.

reference,reference.

reference
  • reference MM reference(reference),reference.reference.
  • reference,reference 22 reference.
  • reference,reference.
  • reference nn reference.reference (Z/6Z)∖{0‾}(\mathbf Z/6\mathbf Z)\setminus\{\overline 0\} reference,2‾×3‾=0‾\overline 2\times\overline 3=\overline 0 reference,reference(reference,reference).

reference,reference.reference,reference,reference.

reference

reference GG reference ⋅\cdot,reference,reference (G,⋅)(G,\cdot) reference reference(semigroup).

reference

reference (G,⋅)(G,\cdot),reference,reference (G,⋅)(G,\cdot) reference reference(monoid).

reference

reference,(N+,+)(\mathbf N_+,+) reference,reference (Z,×)(\mathbf Z,\times) reference.

reference,reference,reference.reference,reference Abel reference,reference.

Abel reference

reference (G,⋅)(G,\cdot),reference ⋅\cdot reference(commutative property),reference a,b∈Ga,b\in G,reference a⋅b=b⋅aa\cdot b=b\cdot a,reference (G,⋅)(G,\cdot) reference Abel reference(Abelian group)reference reference(communicate group).

Abel reference Abel reference
  • reference (Z,+)(\mathbf Z,+) reference Abel reference.
  • reference n≥3n\ge3 reference,reference SnS_n reference Abel reference.

reference.reference,reference reference reference.

reference

reference.

reference

reference RR reference +:R×R→R+:R\times R\rightarrow R reference ⋅:R×R→R\cdot:R\times R\rightarrow R,reference,reference (R,+,⋅)(R,+,\cdot) reference reference(ring):

  1. (R,+)(R,+) reference Abel reference,reference 00,reference a∈Ra\in R reference ++ reference −a-a.
  2. (R,⋅)(R,\cdot) reference,reference ⋅\cdot reference.
  3. reference(distributive property):reference a,b,c∈Ra,b,c\in R,reference a⋅(b+c)=a⋅b+a⋅ca\cdot(b+c)=a\cdot b+a\cdot c reference (a+b)⋅c=a⋅c+b⋅c(a+b)\cdot c=a\cdot c+b\cdot c.

reference,reference ++ reference ⋅\cdot reference,reference,reference reference(zero),reference(reference)reference reference(identity).reference、reference,reference.

reference

reference,reference;reference,reference reference(rng reference pseudo-ring).reference.reference2.

reference,reference.reference,reference,reference.

reference

reference (R,+,⋅)(R,+,\cdot),reference,reference,reference 11,reference (R,+,⋅)(R,+,\cdot) reference reference(ring with identity).

reference

reference (R,+,⋅)(R,+,\cdot),reference 00 reference a∈Ra\in R,reference(reference a−1a^{-1}),reference (R,+,⋅)(R,+,\cdot) reference reference(division ring).

reference

reference (R,+,⋅)(R,+,\cdot),reference,reference (R,+,⋅)(R,+,\cdot) reference reference(commutative ring).

reference,reference 00 reference.reference 0=0⋅a=a⋅00 = 0\cdot a = a\cdot 03.reference,reference.reference,reference,reference.reference(reference).

reference,reference,reference,reference R∖{0}R\setminus\{0\}.reference,reference.

reference

reference (R,+,⋅)(R,+,\cdot),reference b∈Rb\in R reference b≠0b\ne 0,reference a⋅b=0a\cdot b=0 reference b⋅a=0b\cdot a=0,reference aa reference reference(zero divisor).

reference(reference)

reference (R,+,⋅)(R,+,\cdot),reference aa reference,reference b∈Rb\in R,reference a⋅b=b⋅a=1a\cdot b=b\cdot a=1,reference a∈Ra\in R reference reference,reference reference(unit).

「reference」reference「reference」

reference.reference,reference「reference」reference「reference」.

reference,reference.reference,reference,reference.

reference,reference,reference (R∖{0},⋅)(R\setminus\{0\},\cdot) reference.reference,reference,reference.

reference

reference (R,+,⋅)(R,+,\cdot),reference,reference,reference,reference(integral domain).

reference,reference.

reference

reference RR reference a,b,c∈Ra,b,c\in R reference a≠0a\neq 0,reference ab=acab=ac,reference b=cb=c.

reference,reference,reference.reference.

reference(reference)

reference (R,+,⋅)(R,+,\cdot),reference R×R^\times reference RR reference,reference (R×,⋅)(R^\times,\cdot) reference,reference RR reference reference(multiplicative group),reference reference(unit group).

reference.

reference
  • reference(zero ring):reference {0}\{0\} reference ++ reference ×\times reference,reference.reference,reference.

  • reference:reference Z\mathbf Z reference ++ reference ×\times reference (Z,+,×)(\mathbf Z,+,\times).reference,reference,reference.

  • reference:reference RR,reference reference R[x]R[x].reference RR reference,reference.

  • reference(quaternion):reference,reference H={a+bi+cj+dk:a,b,c,d∈R}\mathbf H=\{a+b\mathrm{i}+c\mathrm{j}+d\mathrm{k}:a,b,c,d\in\mathbf R\},reference,reference,i,j,k\mathrm{i},\mathrm{j},\mathrm{k} reference

    i2=j2=k2=−1, ij=−ji=k, jk=−kj=i, ki=−ik=j.\mathrm{i}^2=\mathrm{j}^2=\mathrm{k}^2=-1,\ \mathrm{i}\mathrm{j}=-\mathrm{j}\mathrm{i}=\mathrm{k},\ \mathrm{j}\mathrm{k}=-\mathrm{k}\mathrm{j}=\mathrm{i},\ \mathrm{k}\mathrm{i}=-\mathrm{i}\mathrm{k}=\mathrm{j}.

    reference,H\mathbf H reference,reference,reference.

  • reference 2Z2\mathbf Z,reference,reference,reference,reference.

  • reference nn reference Z/nZ\mathbf Z/n\mathbf Z reference,reference,reference(reference 1ˉ\bar 1).reference,reference nn reference.reference,reference nn reference,reference (Z/nZ,+,×)(\mathbf Z/n\mathbf Z, +,\times) reference;reference,reference,reference.reference ((Z/nZ)×,×)((\mathbf Z/n\mathbf Z)^\times,\times) reference nn reference.

  • reference:reference RR reference nn reference Mn(R)M_n(R).reference,reference,reference.

  • reference AA reference P(A)\mathcal P(A),reference △\triangle reference ∩\cap reference,reference (P(A),△,∩)(\mathcal P(A),\triangle,\cap) reference.reference,reference,reference,reference.

reference,reference,reference,reference reference reference.

reference

reference.reference,reference.reference.

reference

reference FF reference +:F×F→F+:F\times F\rightarrow F reference ⋅:F×F→F\cdot:F\times F\rightarrow F,reference,reference (F,+,⋅)(F,+,\cdot) reference reference(field):

  1. (F,+)(F,+) reference Abel reference,reference 00,reference a∈Fa\in F reference ++ reference −a-a.
  2. (F∖{0},⋅)(F\setminus\{0\},\cdot) reference Abel reference,reference 11,reference a∈F∖{0}a\in F\setminus\{0\} reference ⋅\cdot reference a−1a^{-1}.

reference,reference、reference、reference、reference.

reference.

reference
  • reference:reference Q\mathbf Q,reference R\mathbf R reference C\mathbf C reference.

  • reference(finite field):reference pp reference Z/pZ\mathbf Z/p\mathbf Z reference.reference,reference,reference,reference.

  • reference(fraction field):reference (R,+,⋅)(R,+,\cdot) reference,reference ab−1ab^{-1} reference QQ.reference,reference R×(R∖{0})R\times(R\setminus\{0\}) reference:(a1,b1)∼(a2,b2)(a_1,b_1)\sim(a_2,b_2) reference a1b2=a2b1a_1b_2=a_2b_1.reference,reference QQ reference R×(R∖{0})/∼R\times(R\setminus\{0\})/\sim,reference,(a,b)(a,b) reference ab−1ab^{-1}.reference

    a1b1−1+a2b2−1=(a1⋅b2+a2⋅b1)(b1⋅b2)−1,(a1b1−1)⋅(a2b2−1)=(a1⋅a2)(b1⋅b2)−1\begin{aligned} a_1b_1^{-1}+a_2b_2^{-1} &= (a_1\cdot b_2+a_2\cdot b_1)(b_1\cdot b_2)^{-1},\\ (a_1b_1^{-1})\cdot(a_2b_2^{-1}) &= (a_1\cdot a_2)(b_1\cdot b_2)^{-1} \end{aligned}

    reference (Q,+,⋅)(Q,+,\cdot) reference,reference RR reference.reference,reference (Q,+,×)(\mathbf Q,+,\times) reference (Z,+,×)(\mathbf Z,+,\times) reference.

  • reference(quadratic field):reference Q\mathbf Q reference d\sqrt d reference,reference d≠0,1d\neq 0,1 reference.reference reference.

reference,reference.reference,reference.reference,reference,reference Galois reference.reference,reference.reference,reference reference reference.

reference

reference,reference,reference.

???+ note "【reference】"reference DP"& reference(reference)" reference nn reference,reference mm reference.reference.reference.

reference

reference DP reference,reference reference,reference.reference,reference.

reference,reference,reference DP reference.reference [1,n][1,n] reference,reference ii reference(11)reference(00).reference,[1,i][1,i] reference fi,1f_{i,1} reference fi,0f_{i,0}.reference,reference DP reference

fi,1=wi+fi−1,0,fi,0=max⁡{fi−1,1,fi−1,0}.\begin{aligned} f_{i,1}&=w_{i}+f_{i-1,0},\\ f_{i,0}&=\max\{f_{i-1,1},f_{i-1,0}\}. \end{aligned}

reference (f0,1,f0,0)=(0,0)(f_{0,1},f_{0,0})=(0,0),reference max⁡{fn,1,fn,0}\max\{f_{n,1},f_{n,0}\}.reference ii reference,reference

(fi,1,fi,0)=g(fi−1,1,fi−1,0;wi).(f_{i,1},f_{i,0})=g(f_{i-1,1},f_{i-1,0};w_i).

reference R2\mathbf R^2 reference R2\mathbf R^2 reference,reference (fi−1,1,fi−1,0)(f_{i-1,1},f_{i-1,0}) reference (fi,1,fi,0)(f_{i,1},f_{i,0}),reference,reference.reference.

reference,reference g(⋅;wi)g(\cdot;w_i) reference,reference R2\mathbf R^2 reference R2\mathbf R^2 reference.reference,reference R∪{−∞}\mathbf R\cup\{-\infty\} reference,reference max⁡\max reference、++ reference,reference R∪{−∞}\mathbf R\cup\{-\infty\} reference,reference,−∞-\infty reference,00 reference.reference,reference.reference4,reference (R∪{−∞},max⁡,+)(\mathbf R\cup\{-\infty\},\max,+) reference reference(tropical semiring).

reference (R,⊕,⊗)(R,\oplus,\otimes),reference.reference m×nm\times n reference A=(aij)A=(a_{ij}) reference n×pn\times p reference B=(bjk)B=(b_{jk}),reference ABAB reference (cik)(c_{ik}),reference

cik=⨁j=1n(bij⊗cjk)=max⁡1≤j≤n  (bij+cjk).c_{ik} = \bigoplus_{j=1}^n(b_{ij}\otimes c_{jk}) = \max_{1\le j\le n}\;(b_{ij}+c_{jk}).

reference,reference,reference

(fi,1fi,0)=(−∞wi00)(fi−1,1fi−1,0).\left(\begin{matrix}f_{i,1}\\f_{i,0}\end{matrix}\right) =\left(\begin{matrix}-\infty&w_i\\0&0\end{matrix}\right)\left(\begin{matrix}f_{i-1,1}\\f_{i-1,0}\end{matrix}\right).

reference,reference DP reference.

reference.reference ii,reference S(i)S(i),reference DP reference

fi,1=wi+∑j∈S(i)fj,0,fi,0=∑j∈S(i)max⁡{fj,1,fj,0}.\begin{aligned} f_{i,1}&=w_i+\sum_{j\in S(i)}f_{j,0},\\ f_{i,0}&=\sum_{j\in S(i)}\max\{f_{j,1},f_{j,0}\}. \end{aligned}

reference,reference.reference hh reference ii reference,reference

fi,1=wi+fh,0+gi,1,fi,0=max⁡{fj,0,fj,1}+gi,0,\begin{aligned} f_{i,1}&=w_i+f_{h,0}+g_{i,1},\\ f_{i,0}&=\max\{f_{j,0},f_{j,1}\}+g_{i,0}, \end{aligned}

reference,

gi,1=∑j∈S(i), j≠hfj,0,gi,0=∑j∈S(i), j≠hmax⁡{fj,1,fj,0}\begin{aligned} g_{i,1}&=\sum_{j\in S(i),\ j\neq h}f_{j,0},\\ g_{i,0}&=\sum_{j\in S(i),\ j\neq h}\max\{f_{j,1},f_{j,0}\} \end{aligned}

reference.reference,reference,reference,reference.reference,reference O(log⁡2n)O(\log^2n) reference,reference O(log⁡n)O(\log n),reference LCT reference.

reference.reference max⁡\max reference min⁡\min,reference.reference nn reference AA reference nn reference(reference)reference,reference,AkA^k reference (i,j)(i,j) reference ii reference kk reference jj reference;reference,AnA^n reference.reference,reference O(n3)O(n^3) reference Floyd reference.

reference

Footnotes

  1. reference OI Wiki reference. ↩

  2. Ring(mathematics)- Wikipedia ↩

  3. reference 0⋅a+0=0⋅a=(0+0)⋅a=0⋅a+0⋅a0\cdot a+0 = 0\cdot a = (0+0)\cdot a = 0\cdot a + 0\cdot a,reference,reference,reference,reference.reference. ↩

  4. reference(semiring)reference,reference、reference.reference Wikipedia. ↩

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