This article contains a list of sample
Hilbert-style deductive system
A formal system is an abstract structure used for inferring theorems from axioms according to a set of rules. These rules, which are used for carrying out the inference of theorems from axioms, are the logical calculus of the formal system.
A fo ...
s for
propositional logic
Propositional calculus is a branch of logic. It is also called propositional logic, statement logic, sentential calculus, sentential logic, or sometimes zeroth-order logic. It deals with propositions (which can be true or false) and relations ...
s.
Classical propositional calculus systems
Classical propositional calculus is the standard propositional logic. Its intended semantics is
bivalent and its main property is that it is
strongly complete, otherwise said that whenever a formula semantically follows from a set of premises, it also follows from that set syntactically. Many different equivalent complete axiom systems have been formulated. They differ in the choice of basic
connectives used, which in all cases have to be
functionally complete (i.e. able to express by composition all ''n''-ary
truth tables), and in the exact complete choice of axioms over the chosen basis of connectives.
Implication and negation
The formulations here use implication and negation
as functionally complete set of basic connectives. Every logic system requires at least one non-nullary
rule of inference
In the philosophy of logic, a rule of inference, inference rule or transformation rule is a logical form consisting of a function which takes premises, analyzes their syntax, and returns a conclusion (or conclusions). For example, the rule of ...
. Classical propositional calculus typically uses the rule of
modus ponens:
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We assume this rule is included in all systems below unless stated otherwise.
Frege's axiom system:
[Yasuyuki Imai, Kiyoshi Iséki, On axiom systems of propositional calculi, I, Proceedings of the Japan Academy. Volume 41, Number 6 (1965), 436–439.]
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Hilbert's axiom system:
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Łukasiewicz
Łukasiewicz is a Polish surname. It comes from the given name Łukasz (Lucas). It is found across Poland, particularly in central regions. It is related to the surnames Łukaszewicz and Lukashevich.
People
* Antoni Łukasiewicz (born 1983), ...
's axiom systems:
*First:
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*Second:
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*Third:
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*Fourth:
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Łukasiewicz and
Tarski's axiom system:
[Part XIII: Shôtarô Tanaka. On axiom systems of propositional calculi, XIII. Proc. Japan Acad., Volume 41, Number 10 (1965), 904–907.]
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Carew Arthur Meredith, Meredith's axiom system:
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Elliott Mendelson, Mendelson's axiom system:
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Russell
Russell may refer to:
People
* Russell (given name)
* Russell (surname)
* Lady Russell (disambiguation)
* Lord Russell (disambiguation)
Places Australia
*Russell, Australian Capital Territory
*Russell Island, Queensland (disambiguation)
**Ru ...
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Sobociński's axiom systems:
*First:
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*Second:
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Implication and falsum
Instead of negation, classical logic can also be formulated using the functionally complete set
of connectives.
Tarski–
Bernays Bernays is a surname. Notable people with the surname include:
* Adolphus Bernays (1795–1864), professor of German in London; brother of Isaac Bernays and father of:
** Lewis Adolphus Bernays (1831–1908), public servant and agricultural writer ...
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Wajsberg axiom system:
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Church's axiom system:
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Meredith's axiom systems:
*First:
[[Fitelson, 2001]
"New Elegant Axiomatizations of Some Sentential Logics"
by Branden Fitelson["Some New Results in Logical Calculi Obtained Using Automated Reasoning", Zac Ernst, Ken Harris, & Branden Fitelson, http://www.mcs.anl.gov/research/projects/AR/award-2001/fitelson.pdf]
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Negation and disjunction
Instead of implication, classical logic can also be formulated using the functionally complete set
of connectives. These formulations use the following rule of inference;
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Russell–Bernays axiom system:
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Meredith's axiom systems:
*First:
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*Second:
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*Third:
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Dually, classical propositional logic can be defined using only conjunction and negation.
Sheffer's stroke
Because Sheffer's stroke (also known as NAND operator) is
functionally complete, it can be used to create an entire formulation of propositional calculus. NAND formulations use a rule of inference called
Nicod
Jean George Pierre Nicod (1 June 1893, in France – 16 February 1924, in Geneva, Switzerland) was a French philosopher and logician, best known for his work on propositional logic and induction.
Biography
Nicod's main contribution to formal log ...
's modus ponens:
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Nicod's axiom system:
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