代数中最令人畏惧的算法为何如此简单
当我开始为我的代数引擎 RomiMath 用 TypeScript 实现布赫伯格算法时,我发现了一个令人惊讶的事实:这个被认为是计算代数中最复杂的算法之一,实际上只是纯粹的机械操作。
让我们一步一步地将其简化为易于理解的内容,不做不必要的抽象。
1. 单项式(简单明了)
单项式就是一个项。加法(+)和减法(-)将单项式分开。
示例:25<i>4 + 15</i>x - 2 有 3 个单项式。
在代码中:
```typescript
class Monomial {
coefficient: number; // 例如,5,-2
variables: string[]; // 例如,['x', 'y']
exponents: number[]; // 例如,[2, 1] 表示 x²y
}
```
2. 次数(超级简单)
次数就是指数的总和:
```
3x²y → 次数 = 2 + 1 = 3
5x → 次数 = 1
7 → 次数 = 0
```
3. 词典顺序(比看起来简单)
这就像在字典中排列单词:
```
x > y > z > w
x³ > x²y¹⁰⁰⁰ (因为 3 > 2)
x²y > x²z (因为 y > z)
xy > x (因为它有更多的变量)
```
4. 布赫伯格算法(逐步解析)
步骤 1:取两个多项式
P1: x² + y - 1
P2: x + y² - 2
步骤 2:查看它们的“主项”
```
LT(P1) = x² (因为 x² > y > -1)
LT(P2) = x (因为 x > y² > -2)
```
步骤 3:计算这些项的“最小公倍数”
```
LCM(x², x) = x² (指数的最大值:max(2,1) = 2)
```
步骤 4:进行“智能减法”(S-多项式)
```
S(P1,P2) = (x²/x²)P1 - (x²/x)P2
= (1)(x² + y - 1) - (x)(x + y² - 2)
= (x² + y - 1) - (x² + xy² - 2x)
= -xy² + 2x + y - 1
```
步骤 5:与已有的结果进行简化
```
尝试使用 P1 和 P2 来简化结果
如果不能简化为零 → 新多项式!
```
步骤 6:重复直到没有新项出现
真正的精髓
布赫伯格算法实际上就是:
```
while (还有对) {
1. 取两个多项式
2. 进行它们的“智能减法”
3. 简化结果
4. 如果还有新项,添加到基底
}
```
这并不比跟随食谱复杂。
为什么这很重要
我在 TypeScript 中实现了这个算法,现在它可以在浏览器中在几秒钟内解决 7 个变量的系统。复杂性并不在于理解算法,而在于克服对数学符号的恐惧。
当你将“高级”概念分解为机械操作时,一切都变得可接近。
有没有其他人也有过这样的经历:发现一个“复杂”的概念实际上在分解后变得简单?
查看原文
When I started implementing Buchberger's algorithm in TypeScript for my algebraic engine RomiMath, I discovered something surprising: this algorithm, considered one of the most complex in computational algebra, is actually pure mechanics.<p>Let's break it down to earth, step by step, without unnecessary abstractions.
1. Monomials (Without Complications)<p>A monomial is simply a term. Sums (+) and subtractions (-) divide monomials.<p>Example: 25<i>4 + 15</i>x - 2 has 3 monomials.<p>In code:<p>class Monomial {
coefficient: number; // e.g., 5, -2
variables: string[]; // e.g., ['x', 'y']
exponents: number[]; // e.g., [2, 1] for x²y
}<p>2. Degree (Super Simple)<p>Degree is just the sum of exponents:<p><pre><code> 3x²y → degree = 2 + 1 = 3
5x → degree = 1
7 → degree = 0
</code></pre>
3. Lexicographic Order (Easier Than It Seems)<p>It's like ordering words in a dictionary:<p><pre><code> x > y > z > w
x³ > x²y¹⁰⁰⁰ (because 3 > 2)
x²y > x²z (because y > z)
xy > x (because it has more variables)
</code></pre>
4. Buchberger's Algorithm (Step by Step)<p>Step 1: Take Two Polynomials<p>P1: x² + y - 1
P2: x + y² - 2<p>Step 2: Look at Their "Leading Terms"<p><pre><code> LT(P1) = x² (because x² > y > -1)
LT(P2) = x (because x > y² > -2)
</code></pre>
Step 3: Calculate the "LCM" of Those Terms<p><pre><code> LCM(x², x) = x² (maximum of exponents: max(2,1) = 2)
</code></pre>
Step 4: Do the "Smart Subtraction" (S-polynomial)<p>S(P1,P2) = (x²/x²)<i>P1 - (x²/x)</i>P2
= (1)<i>(x² + y - 1) - (x)</i>(x + y² - 2)
= (x² + y - 1) - (x² + xy² - 2x)
= -xy² + 2x + y - 1<p>Step 5: Simplify Against What We Already Have<p><pre><code> Try to reduce the result using P1 and P2
If it doesn't reduce to zero → NEW POLYNOMIAL!
</code></pre>
Step 6: Repeat Until Nothing New Appears<p>The Real Essence<p>Buchberger is just:<p>while (pairs remain) {
1. Take two polynomials
2. Do their "smart subtraction"
3. Simplify the result
4. If something new remains, add it to the basis
}<p>It's no more complex than following a cooking recipe.<p>Why This Matters<p>I implemented this algorithm in TypeScript and it now solves 7-variable systems in seconds in the browser. The complexity wasn't in understanding the algorithm, but in overcoming the fear of mathematical notation.<p>When you decompose "advanced" concepts into mechanical operations, everything becomes accessible.<p>Has anyone else had that experience of discovering that a "complex" concept was actually simple once they broke it down?