大卫.希尔伯特简介

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原文连接：http://en.wikipedia.org/wiki/David_Hilbert

David Hilbert

David Hilbert
David Hilbert (1912)
Born	January 23, 1862(1862-01-23) Königsberg or Wehlau (today Znamensk, Kaliningrad Oblast), Province of Prussia
Died	February 14, 1943 (aged 81) Göttingen, Germany
Residence	Germany
Nationality	German
Fields	Mathematician and Philosopher

David Hilbert (January 23, 1862 – February 14, 1943) was a German mathematician, recognized as one of the most influential and universal mathematicians of the 19th and early 20th centuries. He discovered or developed a broad range of fundamental ideas in many areas, including invariant theory and the axiomatization of geometry. He also formulated the theory of Hilbert spaces,[1] one of the foundations of functional analysis.

Hilbert adopted and warmly defended Georg Cantor's set theory and transfinite numbers. A famous example of his leadership in mathematics is his 1900 presentation of a collection of problems that set the course for much of the mathematical research of the 20th century.

Hilbert and his students contributed significantly to establishing rigor and some tools to the mathematics used in modern physics. He is also known as one of the founders of proof theory, mathematical logic and the distinction between mathematics and metamathematics.[2][citation needed]

[edit] Life

Hilbert, the first of two children and only son of Otto and Maria Therese (Erdtmann) Hilbert, was born in either Königsberg (according to Hilbert's own statement) or in Wehlau (today Znamensk, Kaliningrad Oblast)) near Königsberg where his father was occupied at the time of his birth in the Province of Prussia.[3] In the fall of 1872, he entered the Friedrichskolleg Gymnasium (the same school that Immanuel Kant had attended 140 years before), but after an unhappy duration he transferred (fall 1879) to and graduated from (spring 1880) the more science-oriented Wilhelm Gymnasium.[4] Upon graduation he enrolled (autumn 1880) at the University of Königsberg, the "Albertina". In the spring of 1882, Hermann Minkowski (two years younger than Hilbert and also a native of Königsberg but so talented he had graduated early from his gymnasium and gone to Berlin for three semesters),[5] returned to Königsberg and entered the university. "Hilbert knew his luck when he saw it. In spite of his father's disapproval, he soon became friends with the shy, gifted Minkowski."[6] In 1884, Adolf Hurwitz arrived from Göttingen as an Extraordinarius, i.e., an associate professor. An intense and fruitful scientific exchange between the three began and especially Minkowski and Hilbert would exercise a reciprocal influence over each other at various times in their scientific careers. Hilbert obtained his doctorate in 1885, with a dissertation, written under Ferdinand von Lindemann, titled Über invariante Eigenschaften spezieller binärer Formen, insbesondere der Kugelfunktionen ("On the invariant properties of special binary forms, in particular the spherical harmonic functions").

Hilbert remained at the University of Königsberg as a professor from 1886 to 1895. In 1892, Hilbert married Käthe Jerosch (1864–1945), "the daughter of a Konigsberg merchant, an outspoken young lady with an independence of mind that matched his own".[7] While at Königsberg they had their one child Franz Hilbert (1893–1969). In 1895, as a result of intervention on his behalf by Felix Klein he obtained the position of Chairman of Mathematics at the University of Göttingen, at that time the best research center for mathematics in the world and where he remained for the rest of his life.

His son Franz would suffer his entire life from an (undiagnosed) mental illness, his inferior intellect a terrible disappointment to his father and this tragedy a matter of distress to the mathematicians and students at Göttingen.[8] Sadly, Minkowski — Hilbert's "best and truest friend"[9] — would die prematurely of a ruptured appendix in 1909.

Math department in Göttingen where Hilbert worked from 1895 until his retirement in 1930

[edit] The Göttingen school

Among the students of Hilbert, there were Hermann Weyl, the champion of chess Emanuel Lasker, Ernst Zermelo, and Carl Gustav Hempel. John von Neumann was his assistant. At the University of Göttingen, Hilbert was surrounded by a social circle of some of the most important mathematicians of the 20th century, such as Emmy Noether and Alonzo Church.

Among his 69 Ph.D. students in Göttingen were many who later became famous mathematicians, including (with date of thesis): Otto Blumenthal (1898), Felix Bernstein (1901), Hermann Weyl (1908), Richard Courant (1910), Erich Hecke (1910), Hugo Steinhaus (1911), Wilhelm Ackermann (1925).[10] Between 1902 and 1939 Hilbert was editor of the Mathematische Annalen, the leading mathematical journal of the time.

Good—he did not have enough imagination to become a mathematician.

—Hilbert's response upon hearing that one of his students had dropped out to study poetry.[11]

[edit] Later years

Hilbert lived to see the Nazis purge many of the prominent faculty members at University of Göttingen, in 1933.[12] Among those forced out were Hermann Weyl, who had taken Hilbert's chair when he retired in 1930, Emmy Noether and Edmund Landau. One of those who had to leave Germany was Paul Bernays, Hilbert's collaborator in mathematical logic, and co-author with him of the important book Die Grundlagen der Mathematik (which eventually appeared in two volumes, in 1934 and 1939). This was a sequel to the Hilbert – Ackermann book Principles of Mathematical Logic from 1928.

About a year later, he attended a banquet, and was seated next to the new Minister of Education, Bernhard Rust. Rust asked, "How is mathematics in Göttingen now that it has been freed of the Jewish influence?" Hilbert replied, "Mathematics in Göttingen? There is really none any more."[13]

Hilbert's tomb: Wir müssen wissen Wir werden wissen

By the time Hilbert died in 1943, the Nazis had nearly completely restructured the university, many of the former faculty being either Jewish or married to Jews. Hilbert's funeral was attended by fewer than a dozen people, only two of whom were fellow academics, among them Arnold Sommerfeld, a theoretical physicist and also a son of the City of Königsberg.[14] News of his death only became known to the wider world six months after he had died.

On his tombstone, at Göttingen, one can read his epitaph, the famous lines he had spoken at the end of his retirement address to the Society of German Scientists and Physicians in the fall of 1930:[15]

Wir müssen wissen.

Wir werden wissen.

As translated into English the inscriptions read:

We must know.

We will know.

(Ironically, the day before Hilbert pronounced this phrase at the 1930 annual meeting of the Society of German Scientists and Physicians, Kurt Gödel—in a roundtable discussion during the Conference on Epistemology held jointly with the Society meetings—tentatively announced the first expression of his (now-famous) incompleteness theorem,[16] the news of which would make Hilbert "somewhat angry".)[17]

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[edit] Later years

Hilbert lived to see the Nazis purge many of the prominent faculty members at University of Göttingen, in 1933.[12] Among those forced out were Hermann Weyl, who had taken Hilbert's chair when he retired in 1930, Emmy Noether and Edmund Landau. One of those who had to leave Germany was Paul Bernays, Hilbert's collaborator in mathematical logic, and co-author with him of the important book Die Grundlagen der Mathematik (which eventually appeared in two volumes, in 1934 and 1939). This was a sequel to the Hilbert – Ackermann book Principles of Mathematical Logic from 1928.

About a year later, he attended a banquet, and was seated next to the new Minister of Education, Bernhard Rust. Rust asked, "How is mathematics in Göttingen now that it has been freed of the Jewish influence?" Hilbert replied, "Mathematics in Göttingen? There is really none any more."[13]

Hilbert's tomb: Wir müssen wissen Wir werden wissen

By the time Hilbert died in 1943, the Nazis had nearly completely restructured the university, many of the former faculty being either Jewish or married to Jews. Hilbert's funeral was attended by fewer than a dozen people, only two of whom were fellow academics, among them Arnold Sommerfeld, a theoretical physicist and also a son of the City of Königsberg.[14] News of his death only became known to the wider world six months after he had died.

On his tombstone, at Göttingen, one can read his epitaph, the famous lines he had spoken at the end of his retirement address to the Society of German Scientists and Physicians in the fall of 1930:[15]

Wir müssen wissen.

Wir werden wissen.

As translated into English the inscriptions read:

We must know.

We will know.

(Ironically, the day before Hilbert pronounced this phrase at the 1930 annual meeting of the Society of German Scientists and Physicians, Kurt Gödel—in a roundtable discussion during the Conference on Epistemology held jointly with the Society meetings—tentatively announced the first expression of his (now-famous) incompleteness theorem,[16] the news of which would make Hilbert "somewhat angry".)[17]

[edit] The finiteness theorem

Hilbert's first work on invariant functions led him to the demonstration in 1888 of his famous finiteness theorem. Twenty years earlier, Paul Gordan had demonstrated the theorem of the finiteness of generators for binary forms using a complex computational approach. The attempts to generalize his method to functions with more than two variables failed because of the enormous difficulty of the calculations involved. Hilbert realized that it was necessary to take a completely different path. As a result, he demonstrated Hilbert's basis theorem: showing the existence of a finite set of generators, for the invariants of quantics in any number of variables, but in an abstract form. That is, while demonstrating the existence of such a set, it was not a constructive proof — it did not display "an object" — but rather, it was an existence proof[18] and relied on use of the Law of Excluded Middle in an infinite extension.

Hilbert sent his results to the Mathematische Annalen. Gordan, the house expert on the theory of invariants for the Mathematische Annalen, was not able to appreciate the revolutionary nature of Hilbert's theorem and rejected the article, criticizing the exposition because it was insufficiently comprehensive. His comment was:

Das ist nicht Mathematik. Das ist Theologie.

(This is not Mathematics. This is Theology.)[19]

Klein, on the other hand, recognized the importance of the work, and guaranteed that it would be published without any alterations. Encouraged by Klein and by the comments of Gordan, Hilbert in a second article extended his method, providing estimations on the maximum degree of the minimum set of generators, and he sent it once more to the Annalen. After having read the manuscript, Klein wrote to him, saying:

Without doubt this is the most important work on general algebra that the Annalen has ever published.[20]

Later, after the usefulness of Hilbert's method was universally recognized, Gordan himself would say:

I have convinced myself that even theology has its merits.[21]

For all his successes, the nature of his proof stirred up more trouble than Hilbert could imagine at the time. Although Kronecker had conceded, Hilbert would later respond to others' similar criticisms that "many different constructions are subsumed under one fundamental idea" — in other words (to quote Reid): "Through a proof of existence, Hilbert had been able to obtain a construction"; "the proof" (i.e. the symbols on the page) was "the object".[21] Not all were convinced. While Kronecker would die soon after, his constructivist banner would be carried forward in full cry by the young Brouwer and his developing intuitionist "school", much to Hilbert's torment in his later years.[22] Indeed Hilbert would lose his "gifted pupil" Weyl to intuitionism — "Hilbert was disturbed by his former student's fascination with the ideas of Brouwer, which aroused in Hilbert the memory of Kronecker".[23] Brouwer the intuitionist in particular raged against the use of the Law of Excluded Middle over infinite sets (as Hilbert had used it). Hilbert would respond:

'Taking the Principle of the Excluded Middle from the mathematician ... is the same as ... prohibiting the boxer the use of his fists.'

The possible loss did not seem to bother Weyl.[24]

[edit] Axiomatization of geometry

Main article: Hilbert's axioms

The text Grundlagen der Geometrie (tr.: Foundations of Geometry) published by Hilbert in 1899 proposes a formal set, the Hilbert's axioms, substituting the traditional axioms of Euclid. They avoid weaknesses identified in those of Euclid, whose works at the time were still used textbook-fashion. Independently and contemporaneously, a 19-year-old American student named Robert Lee Moore published an equivalent set of axioms. Some of the axioms coincide, while some of the axioms in Moore's system are theorems in Hilbert's and vice-versa.

Hilbert's approach signaled the shift to the modern axiomatic method. Axioms are not taken as self-evident truths. Geometry may treat things, about which we have powerful intuitions, but it is not necessary to assign any explicit meaning to the undefined concepts. The elements, such as point, line, plane, and others, could be substituted, as Hilbert says, by tables, chairs, glasses of beer and other such objects. It is their defined relationships that are discussed.

Hilbert first enumerates the undefined concepts: point, line, plane, lying on (a relation between points and planes), betweenness, congruence of pairs of points, and congruence of angles. The axioms unify both the plane geometry and solid geometry of Euclid in a single system.

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[edit] The 23 Problems

Main article: Hilbert's problems

He put forth a most influential list of 23 unsolved problems at the International Congress of Mathematicians in Paris in 1900. This is generally reckoned the most successful and deeply considered compilation of open problems ever to be produced by an individual mathematician.

After re-working the foundations of classical geometry, Hilbert could have extrapolated to the rest of mathematics. His approach differed, however, from the later 'foundationalist' Russell-Whitehead or 'encyclopedist' Nicolas Bourbaki, and from his contemporary Giuseppe Peano. The mathematical community as a whole could enlist in problems, which he had identified as crucial aspects of the areas of mathematics he took to be key.

The problem set was launched as a talk "The Problems of Mathematics" presented during the course of the Second International Congress of Mathematicians held in Paris. Here is the introduction of the speech that Hilbert gave:

Who among us would not be happy to lift the veil behind which is hidden the future; to gaze at the coming developments of our science and at the secrets of its development in the centuries to come? What will be the ends toward which the spirit of future generations of mathematicians will tend? What methods, what new facts will the new century reveal in the vast and rich field of mathematical thought?

He presented fewer than half the problems at the Congress, which were published in the acts of the Congress. In a subsequent publication, he extended the panorama, and arrived at the formulation of the now-canonical 23 Problems of Hilbert. The full text is important, since the exegesis of the questions still can be a matter of inevitable debate, whenever it is asked how many have been solved.

Some of these were solved within a short time. Others have been discussed throughout the 20th century, with a few now taken to be unsuitably open-ended to come to closure. Some even continue to this day to remain a challenge for mathematicians.

[edit] Hilbert's program

In 1920 he proposed explicitly a research project (in metamathematics, as it was then termed) that became known as Hilbert's program. He wanted mathematics to be formulated on a solid and complete logical foundation. He believed that in principle this could be done, by showing that:

• all of mathematics follows from a correctly-chosen finite system of axioms; and
• that some such axiom system is provably consistent through some means such as the epsilon calculus.

He seems to have had both technical and philosophical reasons for formulating this proposal. It affirmed his dislike of what had become known as the ignorabimus, still an active issue in his time in German thought, and traced back in that formulation to Emil du Bois-Reymond.

This program is still recognizable in the most popular philosophy of mathematics, where it is usually called formalism. For example, the Bourbaki group adopted a watered-down and selective version of it as adequate to the requirements of their twin projects of (a) writing encyclopedic foundational works, and (b) supporting the axiomatic method as a research tool. This approach has been successful and influential in relation with Hilbert's work in algebra and functional analysis, but has failed to engage in the same way with his interests in physics and logic.

[edit] Functional analysis

Around 1909, Hilbert dedicated himself to the study of differential and integral equations; his work had direct consequences for important parts of modern functional analysis. In order to carry out these studies, Hilbert introduced the concept of an infinite dimensional Euclidean space, later called Hilbert space. His work in this part of analysis provided the basis for important contributions to the mathematics of physics in the next two decades, though from an unanticipated direction. Later on, Stefan Banach amplified the concept, defining Banach spaces. Hilbert space is the most important single idea in the area of functional analysis that grew up around it during the 20th century.[citation needed]

[edit] Physics

Until 1912, Hilbert was almost exclusively a "pure" mathematician. When planning a visit from Bonn, where he was immersed in studying physics, his fellow mathematician and friend Hermann Minkowski joked he had to spend 10 days in quarantine before being able to visit Hilbert. In fact, Minkowski seems responsible for most of Hilbert's physics investigations prior to 1912, including their joint seminar in the subject in 1905.

In 1912, three years after his friend's death, Hilbert turned his focus to the subject almost exclusively. He arranged to have a "physics tutor" for himself.[25] He started studying kinetic gas theory and moved on to elementary radiation theory and the molecular theory of matter. Even after the war started in 1914, he continued seminars and classes where the works of Albert Einstein and others were followed closely.

By 1907 Einstein had framed the fundamentals of his theory of gravity, but then struggled for nearly 8 years with a confounding problem of putting the theory into final form [26]. By early summer 1915, Hilbert's interest in physics had focused him on general relativity, and he invited Einstein to Göttingen to deliver a week of lectures on the subject[27]. Einstein received an enthusiastic reception at Göttingen[28]. Over the summer Einstein learned that Hilbert was also working on the field equations and redoubled his own efforts. During November 1915 Einstein published several papers culminating in "The Field Equations of Gravitation" (see Einstein field equations. Nearly simultaneously David Hilbert published "The Foundations of Physics", an axiomatic derivation of the field equations (see Einstein–Hilbert action ). Hilbert fully credited Einstein as the originator of the theory, and no public priority dispute concerning the field equations ever arose between the two men during their lives[29] (see more at priority ).

Additionally, Hilbert's work anticipated and assisted several advances in the mathematical formulation of quantum mechanics. His work was a key aspect of Hermann Weyl and John von Neumann's work on the mathematical equivalence of Werner Heisenberg's matrix mechanics and Erwin Schrödinger's wave equation and his namesake Hilbert space plays an important part in quantum theory. In 1926 von Neuman showed that if atomic states were understood as vectors in Hilbert space, then they would correspond with both Schrödinger's wave function theory and Heisenberg's matrices.[30]

Throughout this immersion in physics, Hilbert worked on putting rigor into the mathematics of physics. While highly dependent on higher math, the physicist tended to be "sloppy" with it. To a "pure" mathematician like Hilbert, this was both "ugly" and difficult to understand. As he began to understand the physics and how the physicists were using mathematics, he developed a coherent mathematical theory for what he found, most importantly in the area of integral equations. When his colleague Richard Courant wrote the now classic Methods of Mathematical Physics including some of Hilbert's ideas, he added Hilbert's name as author even though Hilbert had not directly contributed to the writing. Hilbert said "Physics is too hard for physicists", implying that the necessary mathematics was generally beyond them; the Courant-Hilbert book made it easier for them.

[edit] Number theory

Hilbert unified the field of algebraic number theory with his 1897 treatise Zahlbericht (literally "report on numbers"). He also resolved a significant number theory problem formulated by Waring in 1770. As with the the finiteness theorem, he used an existence proof that shows there must be solutions for the problem rather than providing a mechanism to produce the answers[31]. He then had little more to publish on the subject; but the emergence of Hilbert modular forms in the dissertation of a student means his name is further attached to a major area.

He made a series of conjectures on class field theory. The concepts were highly influential, and his own contribution is seen in the names of the Hilbert class field and the Hilbert symbol of local class field theory. Results on them were mostly proved by 1930, after breakthrough work by Teiji Takagi that established him as Japan's first mathematician of international stature.

Hilbert did not work in the central areas of analytic number theory, but his name has become known for the Hilbert–Pólya conjecture, for reasons that are anecdotal.

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以前是从他的23个问题听说到希尔伯特这个名字的，一代大师令人景仰！23个问题如下： 　1． 连续统假设 1874年，康托猜测在可列集基数和实数基数之间没有别的基数，这就是著名的连续统假设。1938年，哥德尔证明了连续统假设和世界公认的策梅洛--弗伦克尔集合论公理系统的无矛盾性。1963年，美国数学家科亨证明连续假设和策梅洛--伦克尔集合论公理是彼此独立的。因此，连续统假设不能在策梅洛--弗伦克尔公理体系内证明其正确性与否。希尔伯特第1问题在这个意义上已获解决。 　　2． 算术公理的相容性 欧几里得几何的相容性可归结为算术公理的相容性。希尔伯特曾提出用形式主义计划的证明论方法加以证明。1931年，哥德尔发表的不完备性定理否定了这种看法。1936年德国数学家根茨在使用超限归纳法的条件下证明了算术公理的相容性。 　　1988年出版的《中国大百科全书》数学卷指出，数学相容性问题尚未解决。 　　3． 两个等底等高四面体的体积相等问题 　　问题的意思是，存在两个等边等高的四面体，它们不可分解为有限个小四面体，使这两组四面体彼此全等。M.W.德恩1900年即对此问题给出了肯定解答。 　　4． 两点间以直线为距离最短线问题 此问题提得过于一般。满足此性质的几何学很多，因而需增加某些限制条件。1973年，苏联数学家波格列洛夫宣布，在对称距离情况下，问题获得解决。 　　《中国大百科全书》说，在希尔伯特之后，在构造与探讨各种特殊度量几何方面有许多进展，但问题并未解决。 　　5.一个连续变换群的李氏概念，定义这个群的函数不假定是可微的 这个问题简称连续群的解析性，即：是否每一个局部欧氏群都有一定是李群？中间经冯·诺伊曼（1933，对紧群情形）、庞德里亚金（1939，对交换群情形）、谢瓦荚（1941，对可解群情形）的努力，1952年由格利森、蒙哥马利、齐宾共同解决，得到了完全肯定的结果。 　　6.物理学的公理化 希尔伯特建议用数学的公理化方法推演出全部物理，首先是概率和力学。1933年，苏联数学家柯尔莫哥洛夫实现了将概率论公理化。后来在量子力学、量子场论方面取得了很大成功。但是物理学是否能全盘公理化，很多人表示怀疑。 　　7.某些数的无理性与超越性 1934年，A.O.盖尔方德和T.施奈德各自独立地解决了问题的后半部分，即对于任意代数数α≠0 ，1，和任意代数无理数β证明了αβ 的超越性。 　　8.素数问题 包括黎曼猜想、哥德巴赫猜想及孪生素数问题等。一般情况下的黎曼猜想仍待解决。哥德巴赫猜想的最佳结果属于陈景润（1966），但离最解决尚有距离。目前孪生素数问题的最佳结果也属于陈景润。 　　9．在任意数域中证明最一般的互反律 该问题已由日本数学家高木贞治（1921）和德国数学家E.阿廷1927）解决。 　　10． 丢番图方程的可解性 能求出一个整系数方程的整数根，称为丢番图方程可解。希尔伯特问，能否用一种由有限步构成的一般算法判断一个丢番图方程的可解性？1970年，苏联的IO.B.马季亚谢维奇证明了希尔伯特所期望的算法不存在。 　　11． 系数为任意代数数的二次型 H.哈塞（1929）和C.L.西格尔（1936，1951）在这个问题上获得重要结果。 　　12． 将阿贝尔域上的克罗克定理推广到任意的代数有理域上去 这一问题只有一些零星的结果，离彻底解决还相差很远。 　　13． 不可能用只有两个变数的函数解一般的七次方程 七次方程 的根依赖于3个参数a、b、c，即x=x （a，b，c）。这个函数能否用二元函数表示出来？苏联数学家阿诺尔德解决了连续函数的情形（1957），维士斯金又把它推广到了连续可微函数的情形（1964）。但如果要求是解析函数则问题尚未解决。 　　14． 证明某类完备函数系的有限性 这和代数不变量问题有关。1958年，日本数学家永田雅宜给出了反例。 　　15． 舒伯特计数演算的严格基础 一个典型问题是：在三维空间中有四条直线，问有几条直线能和这四条直线都相交？舒伯特给出了一个直观解法。希尔伯特要求将问题一般化，并给以严格基础。现在已有了一些可计算的方法，它和代数几何学不密切联系。但严格的基础迄今仍未确立。 　　16． 代数曲线和代数曲线面的拓扑问题 这个问题分为两部分。前半部分涉及代数曲线含有闭的分枝曲线的最大数目。后半部分要求讨论 的极限环的最大个数和相对位置，其中X、Y是x、y的n次多项式.苏联的彼得罗夫斯基曾宣称证明了n=2时极限环的个数不超过3，但这一结论是错误的，已由中国数学家举出反例（1979）。 　　17． 半正定形式的平方和表示 一个实系数n元多项式对一切数组(x1,x2,...,xn) 都恒大于或等于0，是否都能写成平方和的形式？1927年阿廷证明这是对的。 　　18． 用全等多面体构造空间 由德国数学家比勃马赫（1910）、荚因哈特（1928）作出部分解决。 　　19． 正则变分问题的解是否一定解析 对这一问题的研究很少。C.H.伯恩斯坦和彼得罗夫斯基等得出了一些结果。 　　20． 一般边值问题 这一问题进展十分迅速，已成为一个很大的数学分支。目前还在继续研究。 　　21． 具有给定单值群的线性微分方程解的存在性证明 已由希尔伯特本人（1905）和H.罗尔（1957）的工作解决。 　　22． 由自守函数构成的解析函数的单值化 它涉及艰辛的黎曼曲面论，1907年P.克伯获重要突破，其他方面尚未解决。 　　23． 变分法的进一步发展出 这并不是一个明确的数学问题，只是谈了对变分法的一般看法。20世纪以来变分法有了很大的发展。

mathabc

高山仰止！

lltt022

非常敬仰他