¡ßTopology
Topology occupies a high position as an integraated mathematics in the
20th century.
Topology means position and form.
Started from Euler's polyhedron theorem, topology was developed
through Poincare's algebraic topology and Brouwer's
fixed point theorem.
Topology is a feld of mathematics in which topological properties
were treated.
It is a kind of geometry which includes one-to-one
correspondence of space, that is to say, mathematicians
study topological properties in topology.
For example, an early discovered topological property of a
simple closed polyhedral surface is the relation
v-e+f=2, where v,e,fdenote the number of vertices,
edges, and faces, respectively of the polyhedral surface. Many theorems including unicursal problem were known.
As the area of mathematics extended to abstraction, so the object
of mathematics expanded from concrete spaces to the abstract ones.
These abstract spaces are called topological spaces.
New area, called, mathematical analysic processmg was made by the way of topology and algebra. Thus
topological algebra and topological space theorem and topological
analysis formed it majorities in mathmatics.
As the above, topological geometry is tepresentative
mathematics in the 20th century.
This topological geometry influenced on the many other
flelds of mathematics.
¡ßAntinomies of Set Theory
The crisis of mathematics was
brought about by the discovery of paradoxes in the fringe of
Cantor's general theory of sets. Since so much of mathematics is permeated
with set concepts and, for that matter, can actually be made to rest upon set
theory as a foundation, the discovery of paradoxes in set theory naturally cast
into doubt the validity of the whole foundational structure of mathematics.
Bertrand Russell discovered in 1902 paradox depending on nothing more
than just the concept of set itself.
Let X denote any set. then, the set of all sets that
are not member of themselves by N
(X¡ôN)¡ê(X
X)
Now take X to be N, and we have the contradiction
(N¡ôN)¡ê(N
N)
Known of these was given by Russell himself in 1919 and concerns the
plight of the barber of a certain village who has enunciated the principle that he
shaves all those persons ans only those persons of the village who do not shave
themselves. The paradoxical nature of this situation is realized when we try to
answer the question, "Does the barber shave himself?" If he does shave himself, then he shouldn't according to his principle; if he doesn't shave himself,
then he should according to his principle.
Other attempts to solve the paradoxes of set theory look for the trouble in
logic, and it must be admitted that the discovery of the paradoxes in the general
theory of sets has brought about a thorough investigation of the foundations of
logic
¡ßPhilosophies of Mathematics
There have arisen three main philosophies, or schools of thought, concerning the foundations of mathematics the so-called logistic, intuitionist, and
formalist schools. Naturally, any modern philosophy of the foundations of
mathematics must, somehow or other, cope with the present crisis in the foundations
of mathematics
¡ÝRussell and Whitegead's LOGICISM:The logistic thesis is that mathematics is a branch of logic. Rather than being just a tool of mathematics, logic becomes the progenitor of
mathematics. All mathematical concepts are to be formulated in terms of logical
concepts, and all theorems of mathematics are to be developed as theorems
of logic; the distinction between mathematics and logic become merely one of
practical convenience.
Allfred North Whitehead(1861-1947) and Bertrand Russell(1872-1970)
duduced natural number system from hypothesis and set of axiem.
They, therefore, identified many parts if mathematics with logic.
To avoid the contradictions of set theory. Principia mathematica employs a "theory of types."
¡ÝBrower's
INTUITIONISM:The intuitionist thesis is that mathematics is to be
built solely by finite constructive methods in the intuitively given sequence of natural
numbers, According to this view, then, at the very base of mathematics lies
a primitive intuition, allied, no doubt, to our temporal sense of before and after,
that allows us to conceive a single object, then one more, then one more, and so on
endlessly.
For the intuitionists, a set cannot be thought
of as a ready-made collection, but must be considered as a law by means of
which the elements of the set can be constructed in a step-by-step fashion. This
concept of set rules out the possibilty of such contradictory sets as "the set of
all sets."
¡ÝHilbert's
FORMALISM:The formalist thesis is that mathematics is concerned with formal symbolic systems. In fact, mathematics is regarded as a collection of
such abstract developments, in which the terms are mere symbols and the
atatements are formulas involving these symbols; the ultimate base of mathematics
does not lie in logic but only in a collectin of prelogical marks or
symbols and in a set of operations with these marks. Since, from this point of view, mathematics is devoid of concrete content and contains only ideal symbolic
elements,the establishment of the consistency of the various bravches of
mathematics becomes an important and necessary part of the formalist program.
Without such an accompanying consistency proof, the whole study is
essentially senseless. In the formalist thesis, we have the axiomatic development
of mathematics pushed to its extreme.
In his Grundlagen der Geometrie.(1899).
Hilbert had sharpened the mathematical method from the material axiomatics
of Euclid to the formal axiomatics of the present day. The formalist point of
view was developed later by Hilbert to meet the crisis caused by the paradexes
of set theory and the challenge to classical mathematics caused by intuitionisric
criticism.
¡ßPostscript
Because the area of 'history of mathematics ' is so wide
that I referred to written by Lee Woo-young and Shin Hang-gyun which is the translation of ¡¸An Introduction to the History of Mathematics¡¹by Howard Eves.
I summarized the changes of eurogean mathematics' history and
I hope that all users of this web page will get
a good understanding about the characteristics and essence of mathematics.