Biot–Savart law: Difference between revisions

From formulasearchengine
Jump to navigation Jump to search
en>EmausBot
m r2.7.2+) (Robot: Modifying ko:비오-사바르 법칙
 
en>Myasuda
m added missing diacritic
Line 1: Line 1:
Hello from Norway. I'm glad to came here. My first name is Janie. <br>I live in a town called Stavanger in nothern Norway.<br>I was also born in Stavanger 39 years ago. Married in November 2012. I'm working at the backery.<br><br>Here is my web site ... [http://Free-Anti-Spyware.com/FreeAntiSpyware.exe Free Anti-malware]
{{Other uses}}
{{coatrack|date=November 2012}}
{{lead rewrite|date=November 2012}}
<!-- I added the odd spaces below so that they will all be rendered with TeX.  In all three browsers on all three platforms I tried, PNG phi looked different enough from HTML phi that I think many people would be confused. (dreish) -->
 
In [[classical logic|classical]] [[deductive logic|deductive]] [[logic]], a '''consistent''' [[theory (mathematical logic)|theory]] is one that does not contain a [[contradiction]].<ref>Tarski 1946 states it this way: "A deductive theory is called CONSISTENT or NON-CONTRADICTORY if no two asserted statements of this theory contradict each other, or in other words, if of any two contradictory sentences . . . at least one cannot be proved," (p. 135) where Tarski defines ''contradictory'' as follows: "With the help of the word ''not'' one forms the NEGATION of any sentence; two sentences, of which the first is a negation of the second, are called CONTRADICTORY SENTENCES" (p. 20). This definition requires a notion of "proof". Gödel in his 1931 defines the notion this way: "The class of ''provable formulas'' is defined to be the smallest class of formulas that contains the axioms and is closed under the relation "immediate consequence", i.e. formula ''c'' of ''a'' and ''b'' is defined as an ''immediate consequence'' in terms of ''modus ponens'' or substitution; cf Gödel 1931 van Heijenoort 1967:601. Tarski defines "proof" informally as "statements follow one another in a definite order according to certain principles . . . and accompanied by considerations intended to establish their validity[true conclusion for all true premises -- Reichenbach 1947:68]" cf Tarski 1946:3. Kleene 1952 defines the notion with respect to either an induction or as to paraphrase) a finite sequence of formulas such that each formula in the sequence is either an axiom or an "immediate consequence" of the preceding formulas; "A ''proof is said to be a proof ''of'' its last formula, and this formula is said to be ''(formally) provable'' or be a ''(formal) theorem" cf Kleene 1952:83.</ref><ref>[[Paraconsistent logic]] ''tolerates'' contradictions, but toleration of contradiction does not entail consistency.</ref> The lack of contradiction can be defined in either semantic or syntactic terms. The semantic definition states that a theory is consistent [[if and only if]] it has a [[Model theory#First-order logic|model]], i.e. there exists an [[interpretation (logic)|interpretation]] under which all [[Well-formed formula|formulas]] in the theory are true. This is the sense used in traditional [[Term logic|Aristotelian logic]], although in contemporary mathematical logic the term '''satisfiable''' is used instead. The syntactic definition states that a theory is consistent if and only if there is no [[Formula (mathematical logic)|formula]] ''P'' such that both ''P'' and its negation are provable from the axioms of the theory under its associated deductive system.
 
If these semantic and syntactic definitions are equivalent for a particular deductive logic, the logic is '''[[Completeness#Logical completeness|complete]]'''.{{clarify|date=May 2012|reason=which notion of cmpleteness is this?}}{{citation needed|date=May 2012}} The completeness of the [[sentential calculus]] was proved by [[Paul Bernays]] in 1918{{Citation needed|date=October 2009}}<ref>van Heijenoort 1967:265 states that Bernays determined the ''independence'' of the axioms of ''Principia Mathematica'', a result not published until 1926, but he says nothing about Bernays proving their ''consistency''.</ref> and [[Emil Post]] in 1921,<ref>Post proves both consistency and completeness of the propositional calculus of PM, cf van Heijenoort's commentary and Post's 1931 ''Introduction to a general theory of elementary propositons'' in van Heijenoort 1967:264ff. Also Tarski 1946:134ff.</ref> while the completeness of [[predicate calculus]] was proved by [[Kurt Gödel]] in 1930,<ref>cf van Heijenoort's commentary and Gödel's 1930 ''The completeness of the axioms of the functional calculus of logic'' in van Heijenoort 1967:582ff</ref> and consistency proofs for arithmetics restricted with respect to the [[Mathematical induction|induction axiom schema]] were proved by Ackermann (1924), von Neumann (1927) and Herbrand (1931).<ref>cf van Heijenoort's commentary and Herbrand's 1930 ''On the consistency of arithmetic'' in van Heijenoort 1967:618ff.</ref> Stronger logics, such as [[second-order logic]], are not complete.
 
A '''consistency proof''' is a [[mathematical proof]] that a particular theory is consistent.  The early development of mathematical [[proof theory]] was driven by the desire to provide finitary consistency proofs for all of mathematics as part of [[Hilbert's program]].  Hilbert's program was strongly impacted by [[Gödel's incompleteness theorems|incompleteness theorems]], which showed that sufficiently strong proof theories cannot prove their own consistency (provided that they are in fact consistent).
 
Although consistency can be proved by means of model theory, it is often done in a purely syntactical way, without any need to reference some model of the logic. The [[cut-elimination]] (or equivalently the [[Normalization property|normalization]] of the [[Curry-Howard|underlying calculus]] if there is one) implies the consistency of the calculus: since there is obviously no cut-free proof of falsity, there is no contradiction in general.
 
==Consistency and completeness in arithmetic and set theory==
In theories of arithmetic, such as [[Peano arithmetic]], there is an intricate relationship between the consistency of the theory and its [[completeness]]. A theory is complete if, for every formula φ in its language, at least one of φ or ¬ φ is a logical consequence of the theory.
 
[[Presburger arithmetic]] is an axiom system for the natural numbers under addition. It is both consistent and complete.
 
[[Gödel's incompleteness theorems]] show that any sufficiently strong effective theory of arithmetic cannot be both complete and consistent. Gödel's theorem applies to the theories of [[Peano arithmetic]] (PA) and [[Primitive recursive arithmetic]] (PRA), but not to [[Presburger arithmetic]].
 
Moreover, Gödel's second incompleteness theorem shows that the consistency of sufficiently strong effective theories of arithmetic can be tested in a particular way. Such a theory is consistent if and only if it does ''not'' prove a particular sentence, called the Gödel sentence of the theory, which is a formalized statement of the claim that the theory is indeed consistent. Thus the consistency of a sufficiently strong, effective, consistent theory of arithmetic can never be proven in that system itself. The same result is true for effective theories that can describe a strong enough fragment of arithmetic &ndash; including set theories such as [[Zermelo–Fraenkel set theory]].  These set theories cannot prove their own Gödel sentences – provided that they are consistent, which is generally believed.
 
Because consistency of ZF is not provable in ZF, the weaker notion '''relative consistency''' is interesting in set theory (and in other sufficiently expressive axiomatic systems). If ''T'' is a [[theory (mathematical logic)|theory]] and ''A'' is an additional [[axiom]], ''T'' + ''A'' is said to be consistent relative to ''T'' (or simply that ''A'' is consistent with ''T'') if it can be proved that
if ''T'' is consistent then ''T'' + ''A'' is consistent. If both ''A'' and ¬''A'' are consistent with ''T'', then ''A'' is said to be [[Independence (mathematical logic)|independent]] of ''T''.
 
== First-order logic ==
 
===Notation===
⊢ (Turnstyle symbol) in the following context of [[Mathematical logic]], means "provable from". That is, a ⊢ b reads: b is provable from a (in some specified formal system) -- see [[List of logic symbols]]) . In other cases, the turnstyle symbol may stand to mean infers; derived from. See: [[List of mathematical symbols]].
 
===Definition===
A set of [[formulas]] <math>\Phi</math> in first-order logic is '''consistent''' (written Con<math>\Phi</math>) [[if and only if]] there is no formula <math>\phi</math> such that <math>\Phi \vdash \phi</math> and <math>\Phi \vdash \lnot\phi</math>.  Otherwise <math>\Phi</math> is '''inconsistent''' and is written Inc<math>\Phi</math>.
 
<math>\Phi</math> is said to be '''simply consistent''' [[if and only if]] for no formula <math>\phi</math> of <math>\Phi</math>, both <math>\phi</math> and the [[negation]] of <math>\phi</math> are theorems of <math>\Phi</math>.
 
<math>\Phi</math> is said to be '''absolutely consistent''' or '''Post consistent''' if and only if at least one formula of <math>\Phi</math> is not a theorem of <math>\Phi</math>.
 
<math>\Phi</math> is said to be '''maximally consistent''' if and only if for every formula <math>\phi</math>, if Con (<math>\Phi \cup \phi</math>)  then  <math>\phi \in \Phi</math>.
 
<math>\Phi</math> is said to '''contain witnesses''' if and only if for every formula of the form <math>\exists x \phi</math> there exists a term <math>t</math> such that <math>(\exists x \phi \to \phi {t \over x}) \in \Phi</math>.  See [[First-order logic]].
 
===Basic results===
# The following are equivalent:
## Inc<math>\Phi</math>
## For all <math>\phi,\; \Phi \vdash \phi.</math>
# Every satisfiable set of formulas is consistent, where a set of formulas <math>\Phi</math> is satisfiable if and only if there exists a model <math>\mathfrak{I}</math> such that <math>\mathfrak{I} \vDash \Phi </math>.
# For all <math>\Phi</math> and <math>\phi</math>:
## if not <math> \Phi \vdash \phi</math>, then Con<math>\left( \Phi \cup \{\lnot\phi\}\right)</math>;
## if Con <math>\Phi</math> and <math>\Phi \vdash \phi</math>, then Con<math> \left(\Phi \cup \{\phi\}\right)</math>;
## if Con <math>\Phi</math>, then Con<math>\left( \Phi \cup \{\phi\}\right)</math> or Con<math>\left( \Phi \cup \{\lnot \phi\}\right)</math>.
# Let <math>\Phi</math> be a maximally consistent set of formulas and contain [[Witness (mathematics)|witnesses]]. For all <math>\phi</math> and <math> \psi </math>:
## if <math> \Phi \vdash \phi</math>, then <math>\phi \in \Phi</math>,
## either <math>\phi \in \Phi</math> or <math>\lnot \phi \in \Phi</math>,
## <math>(\phi \or \psi) \in \Phi</math> if and only if <math>\phi \in \Phi</math> or <math>\psi \in \Phi</math>,
## if <math>(\phi\to\psi) \in \Phi</math> and <math>\phi \in \Phi </math>, then <math>\psi \in \Phi</math>,
## <math>\exists x \phi \in \Phi</math> if and only if there is a term <math>t</math> such that <math>\phi{t \over x}\in\Phi</math>.
 
===Henkin's theorem===
Let <math>\Phi</math> be a maximally consistent set of <math>S</math>-formulas containing [[Witness_(mathematics)#Henkin_witnesses|witnesses]].
 
Define a binary relation <math>\sim</math> on the set of <math>S</math>-terms such that <math>t_0 \sim t_1</math> if and only if <math>\; t_0 \equiv t_1 \in \Phi</math>; and let <math>\overline t \!</math> denote the equivalence class of terms containing <math>t \!</math>; and let <math>T_{\Phi} := \{ \; \overline t \; |\; t \in T^S \} </math> where <math>T^S \!</math> is the set of terms based on the symbol set <math>S \!</math>.
 
Define the <math>S</math>-structure <math>\mathfrak T_{\Phi} </math> over <math> T_{\Phi} \!</math> the '''term-structure''' corresponding to <math>\Phi</math> by:
 
# for <math>n</math>-ary <math>R \in S</math>, <math>R^{\mathfrak T_{\Phi}} \overline {t_0} \ldots \overline {t_{n-1}}</math> if and only if <math>\; R t_0 \ldots t_{n-1} \in \Phi</math>;
# for <math>n</math>-ary <math>f \in S</math>, <math>f^{\mathfrak T_{\Phi}} (\overline {t_0} \ldots \overline {t_{n-1}}) := \overline {f t_0 \ldots t_{n-1}}</math>;
# for <math>c \in S</math>, <math>c^{\mathfrak T_{\Phi}}:= \overline c</math>.
 
Let <math>\mathfrak I_{\Phi} := (\mathfrak T_{\Phi},\beta_{\Phi})</math> be the '''term interpretation''' associated with <math>\Phi</math>, where <math>\beta _{\Phi} (x) := \bar x</math>.
 
<center>
For all <math>\phi</math>, <math>\; \mathfrak I_{\Phi} \vDash \phi</math> if and only if <math> \; \phi \in \Phi</math>.
</center>
 
===Sketch of proof===
There are several things to verify. First, that <math>\sim</math> is an [[equivalence relation]].  Then, it needs to be verified that (1), (2), and (3) are well defined.  This falls out of the fact that <math>\sim</math> is an equivalence relation and also requires a proof that (1) and (2) are independent of the choice of <math> t_0, \ldots ,t_{n-1} </math> class representatives.  Finally, <math> \mathfrak I_{\Phi} \vDash \Phi </math> can be verified by induction on formulas.
 
==See also==
{{Portal|Logic}}
{{Wikiquote}}
*[[Equiconsistency]]
*[[Hilbert's problems]]
*[[Hilbert's second problem]]
*[[Jan Łukasiewicz]]
*[[Paraconsistent logic]]
*[[ω-consistency]]
 
==Footnotes==
<references/>
 
==References==
* [[Stephen Kleene]], 1952 10th impression 1991, ''Introduction to Metamathematics'', North-Holland Publishing Company, Amsterday, New York, ISBN 0-7204-2103-9.
* [[Hans Reichenbach]], 1947, ''Elements of Symbolic Logic'', Dover Publications, Inc. New York, ISBN 0-486-24004-5,
* [[Alfred Tarski]], 1946, ''Introduction to Logic and to the Methodology of Deductive Sciences, Second Edition'', Dover Publications, Inc., New York, ISBN 0-486-28462-X.
* [[Jean van Heijenoort]], 1967, ''From Frege to Gödel: A Source Book in Mathematical Logic'', Harvard University Press, Cambridge, MA, ISBN 0-674-32449-8 (pbk.)
* [[The Cambridge Dictionary of Philosophy]], ''consistency''
* H.D. Ebbinghaus, J. Flum, W. Thomas, '''Mathematical Logic'''
* Jevons, W.S., 1870, ''Elementary Lessons in Logic''
 
==External links==
* Chris Mortensen, [http://plato.stanford.edu/entries/mathematics-inconsistent/ Inconsistent Mathematics], [[Stanford Encyclopedia of Philosophy]]
 
{{Logic}}
 
[[Category:Proof theory]]
[[Category:Hilbert's problems]]
[[Category:Metalogic]]

Revision as of 17:51, 30 December 2013

I'm Fernando (21) from Seltjarnarnes, Iceland.
I'm learning Norwegian literature at a local college and I'm just about to graduate.
I have a part time job in a the office.

my site; wellness [continue reading this..] Template:Coatrack Template:Lead rewrite

In classical deductive logic, a consistent theory is one that does not contain a contradiction.[1][2] The lack of contradiction can be defined in either semantic or syntactic terms. The semantic definition states that a theory is consistent if and only if it has a model, i.e. there exists an interpretation under which all formulas in the theory are true. This is the sense used in traditional Aristotelian logic, although in contemporary mathematical logic the term satisfiable is used instead. The syntactic definition states that a theory is consistent if and only if there is no formula P such that both P and its negation are provable from the axioms of the theory under its associated deductive system.

If these semantic and syntactic definitions are equivalent for a particular deductive logic, the logic is complete.Template:ClarifyPotter or Ceramic Artist Truman Bedell from Rexton, has interests which include ceramics, best property developers in singapore developers in singapore and scrabble. Was especially enthused after visiting Alejandro de Humboldt National Park. The completeness of the sentential calculus was proved by Paul Bernays in 1918Potter or Ceramic Artist Truman Bedell from Rexton, has interests which include ceramics, best property developers in singapore developers in singapore and scrabble. Was especially enthused after visiting Alejandro de Humboldt National Park.[3] and Emil Post in 1921,[4] while the completeness of predicate calculus was proved by Kurt Gödel in 1930,[5] and consistency proofs for arithmetics restricted with respect to the induction axiom schema were proved by Ackermann (1924), von Neumann (1927) and Herbrand (1931).[6] Stronger logics, such as second-order logic, are not complete.

A consistency proof is a mathematical proof that a particular theory is consistent. The early development of mathematical proof theory was driven by the desire to provide finitary consistency proofs for all of mathematics as part of Hilbert's program. Hilbert's program was strongly impacted by incompleteness theorems, which showed that sufficiently strong proof theories cannot prove their own consistency (provided that they are in fact consistent).

Although consistency can be proved by means of model theory, it is often done in a purely syntactical way, without any need to reference some model of the logic. The cut-elimination (or equivalently the normalization of the underlying calculus if there is one) implies the consistency of the calculus: since there is obviously no cut-free proof of falsity, there is no contradiction in general.

Consistency and completeness in arithmetic and set theory

In theories of arithmetic, such as Peano arithmetic, there is an intricate relationship between the consistency of the theory and its completeness. A theory is complete if, for every formula φ in its language, at least one of φ or ¬ φ is a logical consequence of the theory.

Presburger arithmetic is an axiom system for the natural numbers under addition. It is both consistent and complete.

Gödel's incompleteness theorems show that any sufficiently strong effective theory of arithmetic cannot be both complete and consistent. Gödel's theorem applies to the theories of Peano arithmetic (PA) and Primitive recursive arithmetic (PRA), but not to Presburger arithmetic.

Moreover, Gödel's second incompleteness theorem shows that the consistency of sufficiently strong effective theories of arithmetic can be tested in a particular way. Such a theory is consistent if and only if it does not prove a particular sentence, called the Gödel sentence of the theory, which is a formalized statement of the claim that the theory is indeed consistent. Thus the consistency of a sufficiently strong, effective, consistent theory of arithmetic can never be proven in that system itself. The same result is true for effective theories that can describe a strong enough fragment of arithmetic – including set theories such as Zermelo–Fraenkel set theory. These set theories cannot prove their own Gödel sentences – provided that they are consistent, which is generally believed.

Because consistency of ZF is not provable in ZF, the weaker notion relative consistency is interesting in set theory (and in other sufficiently expressive axiomatic systems). If T is a theory and A is an additional axiom, T + A is said to be consistent relative to T (or simply that A is consistent with T) if it can be proved that if T is consistent then T + A is consistent. If both A and ¬A are consistent with T, then A is said to be independent of T.

First-order logic

Notation

⊢ (Turnstyle symbol) in the following context of Mathematical logic, means "provable from". That is, a ⊢ b reads: b is provable from a (in some specified formal system) -- see List of logic symbols) . In other cases, the turnstyle symbol may stand to mean infers; derived from. See: List of mathematical symbols.

Definition

A set of formulas in first-order logic is consistent (written Con) if and only if there is no formula such that and . Otherwise is inconsistent and is written Inc.

is said to be simply consistent if and only if for no formula of , both and the negation of are theorems of .

is said to be absolutely consistent or Post consistent if and only if at least one formula of is not a theorem of .

is said to be maximally consistent if and only if for every formula , if Con () then .

is said to contain witnesses if and only if for every formula of the form there exists a term such that . See First-order logic.

Basic results

  1. The following are equivalent:
    1. Inc
    2. For all
  2. Every satisfiable set of formulas is consistent, where a set of formulas is satisfiable if and only if there exists a model such that .
  3. For all and :
    1. if not , then Con;
    2. if Con and , then Con;
    3. if Con , then Con or Con.
  4. Let be a maximally consistent set of formulas and contain witnesses. For all and :
    1. if , then ,
    2. either or ,
    3. if and only if or ,
    4. if and , then ,
    5. if and only if there is a term such that .

Henkin's theorem

Let be a maximally consistent set of -formulas containing witnesses.

Define a binary relation on the set of -terms such that if and only if ; and let denote the equivalence class of terms containing ; and let where is the set of terms based on the symbol set .

Define the -structure over the term-structure corresponding to by:

  1. for -ary , if and only if ;
  2. for -ary , ;
  3. for , .

Let be the term interpretation associated with , where .

For all , if and only if .

Sketch of proof

There are several things to verify. First, that is an equivalence relation. Then, it needs to be verified that (1), (2), and (3) are well defined. This falls out of the fact that is an equivalence relation and also requires a proof that (1) and (2) are independent of the choice of class representatives. Finally, can be verified by induction on formulas.

See also

Sportspersons Hyslop from Nicolet, usually spends time with pastimes for example martial arts, property developers condominium in singapore singapore and hot rods. Maintains a trip site and has lots to write about after touring Gulf of Porto: Calanche of Piana. Property growth may be attributed as the enhancement of a given space by an individual or a marketing consultant or by a corporation as a whole. Any particular person or organization involved in the above activity will possible be known as a Property Developer. Singapore is admittedly well-known in Asia for its booming property.

As a Singapore citizen and in case you are eligible for the backed loans you may benefit from the backed mortgage rates of the HDB. The HDB can grant a sponsored mortgage to first time house patrons and also to second time house consumers who upgrade to another HDB flats. Beginning of January 2008 ,the Singapore Inter financial institution offered rate (Sibor) has fallen again and is at its lowest since three years. Analysts consider it's going to sink additional throughout 2008. The Sibor is the speed at which bank lend to one another and influences what you pay for a mortgage. Statistics exhibits nonetheless, that local and foreign banks in Singapore don't go on the savings without delay but fairly in a time-frame from about two months. Read Extra Do rising Singapore bankruptcies signal hassle ahead?

One in every of Asia's premier property companies, Keppel Land is recognised for its sterling portfolio of award-profitable residential developments and investment-grade commercial properties in addition to excessive requirements of corporate governance and transparency. Keppel Land is likely one of the largest listed property companies by whole belongings on the Singapore Change. The Group's complete assets amounted to about $13.eight billion as at 31 March 2014. It is usually a element of several stock indices together with the FTSE ST Actual Estate Index, FTSE ST China High Index, FTSE All-World Index, FTSE Asia Pacific ex-Japan Index, FTSE EPRA/NAREIT World Real Property Index and EPRA/NAREIT Index. WOODSVALE PERSONAL CONDOMINIUM CONDO WOODSVALE SHUT, SINGAPORE (DISTRICT thirteen) Industrial

The rise within the nominal value index pales as compared with the 38.2% value hike (34% in actual terms) throughout the 12 months to Q2 2010, a period which noticed the fastest value-rises of the recent increase. Measures were introduced in October 2012 to limit mortgage tenure to 35 years, and to lower to 60% the LTV ratio for loans longer than 30 years, or mortgage durations extending past age sixty five. Client Worth Index for Households in Completely different Revenue Teams Domestic Provide Price Index Home Wholesale Commerce Index Expenditure on Gross Domestic Product at 2005 Market Costs Expenditure on Gross Domestic Product at Current Market Prices Food & Beverage Services Index Authorities Improvement Expenditure Gross Home Product at 2005 Market Costs Gross Home Product at Current Market Prices

Thinking of buying property in Singapore and wish to know extra about particular property launches in Singapore, or to attend their VIP Previews ? If you've ever had the experience of paying for an uncompleted property elsewhere only to see the developer vanish halfway by construction of the venture, you'd be glad to know this isn't one thing that's more likely to occur should you're shopping for property in Singapore. That's as a result of new Singapore property gross sales are very high regulated. This page covers some temporary data on the procedures to buy or purchase property in Singapore. Tips for foreigners or buyers buying condominium, home or other properties in Singapore. the title of the big property developers in singapore; Landed Property Builders step by step raising property prices HDB HUB

Only Singapore citizens and accepted persons should buy Landed 'residential property'as outlined in the Residential Properties Act. Foreigners are eligible to purchaseunits in condominiums or flats which aren't landed dwelling homes. Foreignerswho wish to buy landed property in Singapore should first search the approval ofthe Controller of Residential Property. Your Lawyer's Function in a Property Purchase Pending completion of your buy, your lawyer will lodge a caveat towards the title to the property - this serves to notify the general public (and any third social gathering fascinated in the property) that you've a sound curiosity or declare to the title of the property arising from the contract for the sale and buy. Property was all the time on his thoughts Property

Non-public residential properties investment shall be thought of for software for Everlasting Resident software. A foreigner will be considered for PR status if he invests at the least S$2 million in business set-ups, other funding autos such as venture capital funds, foundations or trusts, and/or private residential properties. Up to 50% of the funding may be in personal residential properties, topic to foreign ownership restrictions underneath the Residential Property Act (RPA). That is to attract and anchor foreign expertise in Singapore.

NASSIM, THE PERSONAL CONDOMINIUM CONDOMINIUM NASSIM HILL, SINGAPORE (DISTRICT 10) NATHAN RESIDENCES NON-PUBLIC CONDOMINIUM HOUSE NATHAN STREET, SINGAPORE (DISTRICT 10) NATHAN SUITES PERSONAL CONDOMINIUM RESIDENCE NATHAN STREET, SINGAPORE (DISTRICT 10) NAUTICAL, THE PRIVATE CONDOMINIUM CONDO JALAN SENDUDOK, SINGAPORE (DISTRICT 27) NINE DEGRESS (LAUNCHING QUICKLY!) PRIVATE CONDOMINIUM APARTMENT TANJONG KATONG ROAD, SINGAPORE (DISTRICT 15) NOUVEL 18 NON-PUBLIC CONDOMINIUM RESIDENCE ANDERSON STREET, SINGAPORE (DISTRICT 09) ONE DUSUN RESIDENCES NON-PUBLIC CONDOMINIUM CONDOMINIUM JALAN DUSUN, BALESTIER ROAD, SINGAPORE (DISTRICT 12) ONE DUSUN RESIDENCES INDUSTRIAL RETAIL STORE HOUSE JALAN DUSUN, BALESTIER ROAD, SINGAPORE (DISTRICT 12) Wing Tai Holdings Ltd Singapore

Footnotes

  1. Tarski 1946 states it this way: "A deductive theory is called CONSISTENT or NON-CONTRADICTORY if no two asserted statements of this theory contradict each other, or in other words, if of any two contradictory sentences . . . at least one cannot be proved," (p. 135) where Tarski defines contradictory as follows: "With the help of the word not one forms the NEGATION of any sentence; two sentences, of which the first is a negation of the second, are called CONTRADICTORY SENTENCES" (p. 20). This definition requires a notion of "proof". Gödel in his 1931 defines the notion this way: "The class of provable formulas is defined to be the smallest class of formulas that contains the axioms and is closed under the relation "immediate consequence", i.e. formula c of a and b is defined as an immediate consequence in terms of modus ponens or substitution; cf Gödel 1931 van Heijenoort 1967:601. Tarski defines "proof" informally as "statements follow one another in a definite order according to certain principles . . . and accompanied by considerations intended to establish their validity[true conclusion for all true premises -- Reichenbach 1947:68]" cf Tarski 1946:3. Kleene 1952 defines the notion with respect to either an induction or as to paraphrase) a finite sequence of formulas such that each formula in the sequence is either an axiom or an "immediate consequence" of the preceding formulas; "A proof is said to be a proof of its last formula, and this formula is said to be (formally) provable or be a (formal) theorem" cf Kleene 1952:83.
  2. Paraconsistent logic tolerates contradictions, but toleration of contradiction does not entail consistency.
  3. van Heijenoort 1967:265 states that Bernays determined the independence of the axioms of Principia Mathematica, a result not published until 1926, but he says nothing about Bernays proving their consistency.
  4. Post proves both consistency and completeness of the propositional calculus of PM, cf van Heijenoort's commentary and Post's 1931 Introduction to a general theory of elementary propositons in van Heijenoort 1967:264ff. Also Tarski 1946:134ff.
  5. cf van Heijenoort's commentary and Gödel's 1930 The completeness of the axioms of the functional calculus of logic in van Heijenoort 1967:582ff
  6. cf van Heijenoort's commentary and Herbrand's 1930 On the consistency of arithmetic in van Heijenoort 1967:618ff.

References

  • Stephen Kleene, 1952 10th impression 1991, Introduction to Metamathematics, North-Holland Publishing Company, Amsterday, New York, ISBN 0-7204-2103-9.
  • Hans Reichenbach, 1947, Elements of Symbolic Logic, Dover Publications, Inc. New York, ISBN 0-486-24004-5,
  • Alfred Tarski, 1946, Introduction to Logic and to the Methodology of Deductive Sciences, Second Edition, Dover Publications, Inc., New York, ISBN 0-486-28462-X.
  • Jean van Heijenoort, 1967, From Frege to Gödel: A Source Book in Mathematical Logic, Harvard University Press, Cambridge, MA, ISBN 0-674-32449-8 (pbk.)
  • The Cambridge Dictionary of Philosophy, consistency
  • H.D. Ebbinghaus, J. Flum, W. Thomas, Mathematical Logic
  • Jevons, W.S., 1870, Elementary Lessons in Logic

External links

Template:Logic