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#1
23 มกราคม 2021, 16:01
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Georg_Cantor
https://en.wikiquote.org/wiki/Georg_Cantor
In mathematics the art of asking questions is more valuable than solving problems. Doctoral thesis (1867); variant translation: In mathematics the art of proposing a question must be held of higher value than solving it. Georg Ferdinand Ludwig Philipp Cantor (March 3 [O.S. February 19] 1845 โ January 6, 1918[1]) was a German mathematician. He created set theory, which has become a fundamental theory in mathematics. Cantor established the importance of one-to-one correspondence between the members of two sets, defined infinite and well-ordered sets, and proved that the real numbers are more numerous than the natural numbers. In fact, Cantor's method of proof of this theorem implies the existence of an infinity of infinities. He defined the cardinal and ordinal numbers and their arithmetic. Cantor's work is of great philosophical interest, a fact he was well aware of.[2] Wiki 24 มกราคม 2021 20:07 : ข้อความนี้ถูกแก้ไขแล้ว 1 ครั้ง, ครั้งล่าสุดโดยคุณ share 
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#2
26 มกราคม 2021, 13:51
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Cantor's work between 1874 and 1884 is the origin of set theory.[34]
Prior to this work, the concept of a set was a rather elementary one that had been used implicitly since the beginning of mathematics, dating back to the ideas of Aristotle. No one had realized that set theory had any nontrivial content. Before Cantor, there were only finite sets (which are easy to understand) and "the infinite" (which was considered a topic for philosophical, rather than mathematical, discussion). By proving that there are (infinitely) many possible sizes for infinite sets, Cantor established that set theory was not trivial, and it needed to be studied. Set theory has come to play the role of a foundational theory in modern mathematics, in the sense that it interprets propositions about mathematical objects (for example, numbers and functions) from all the traditional areas of mathematics (such as algebra, analysis and topology) in a single theory, and provides a standard set of axioms to prove or disprove them. The basic concepts of set theory are now used throughout mathematics.[35] Wiki
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