content_id
stringlengths
14
14
page_title
stringlengths
1
250
section_title
stringlengths
1
1.26k
breadcrumb
stringlengths
1
1.39k
text
stringlengths
9
3.55k
c_yyf8a91sb8zd
Uniqueness case
Summary
Uniqueness_case
In mathematical finite group theory, the uniqueness case is one of the three possibilities for groups of characteristic 2 type given by the trichotomy theorem. The uniqueness case covers groups G of characteristic 2 type with e(G) ≥ 3 that have an almost strongly p-embedded maximal 2-local subgroup for all primes p who...
c_wiuqw5s7m1eg
Vertex of a representation
Summary
Vertex_of_a_representation
In mathematical finite group theory, the vertex of a representation of a finite group is a subgroup associated to it, that has a special representation called a source. Vertices and sources were introduced by Green (1958–1959).
c_ak0r69vi6z84
No free lunch theorem
Summary
No_free_lunch_theorem
In mathematical folklore, the "no free lunch" (NFL) theorem (sometimes pluralized) of David Wolpert and William Macready, alludes to the saying "no such thing as a free lunch", that is, there are no easy shortcuts to success. It appeared in the 1997 "No Free Lunch Theorems for Optimization". Wolpert had previously deri...
c_zmcv9slvsx6y
Kimeme
Algorithm design
Kimeme > Features > Algorithm design
In mathematical folklore, the no free lunch theorem (sometimes pluralized) of David Wolpert and William G. Macready appears in the 1997 "No Free Lunch Theorems for Optimization. "This mathematical result states the need for a specific effort in the design of a new algorithm, tailored to the specific problem to be optim...
c_y178lgcbs02q
Minus-plus sign
In mathematics
Plus–minus_sign > Usage > In mathematics
In mathematical formulas, the ± symbol may be used to indicate a symbol that may be replaced by either the plus and minus signs, + or −, allowing the formula to represent two values or two equations.If x2 = 9, one may give the solution as x = ±3. This indicates that the equation has two solutions: x = +3 and x = −3. A ...
c_et1ak5c099j0
Minus-plus sign
In mathematics
Plus–minus_sign > Usage > In mathematics
+ x 5 5 ! − x 7 7 !
c_5nsft66jssul
Minus-plus sign
In mathematics
Plus–minus_sign > Usage > In mathematics
+ ⋯ ± 1 ( 2 n + 1 ) ! x 2 n + 1 + ⋯ . {\displaystyle \sin \left(x\right)=x-{\frac {x^{3}}{3!
c_v396ql0ee8fw
Minus-plus sign
In mathematics
Plus–minus_sign > Usage > In mathematics
}}+{\frac {x^{5}}{5! }}-{\frac {x^{7}}{7! }}+\cdots \pm {\frac {1}{(2n+1)!
c_nnkx2ii5jj9r
Minus-plus sign
In mathematics
Plus–minus_sign > Usage > In mathematics
}}x^{2n+1}+\cdots ~.} Here, the plus-or-minus sign indicates that the term may be added or subtracted depending on whether n is odd or even; a rule which can be deduced from the first few terms. A more rigorous presentation would multiply each term by a factor of (−1)n, which gives +1 when n is even, and −1 when n is o...
c_t5rhdpv0dla3
Minus-plus sign
In mathematics
Plus–minus_sign > Usage > In mathematics
In older texts one occasionally finds (−)n, which means the same. When the standard presumption that the plus-or-minus signs all take on the same value of +1 or all −1 is not true, then the line of text that immediately follows the equation must contain a brief description of the actual connection, if any, most often o...
c_93zq8lrn6u68
Penrose inequality
Summary
Penrose_inequality
In mathematical general relativity, the Penrose inequality, first conjectured by Sir Roger Penrose, estimates the mass of a spacetime in terms of the total area of its black holes and is a generalization of the positive mass theorem. The Riemannian Penrose inequality is an important special case. Specifically, if (M, g...
c_f1n0z6ykaaxg
Penrose inequality
Summary
Penrose_inequality
This is purely a geometrical fact, and it corresponds to the case of a complete three-dimensional, space-like, totally geodesic submanifold of a (3 + 1)-dimensional spacetime. Such a submanifold is often called a time-symmetric initial data set for a spacetime. The condition of (M, g) having nonnegative scalar curvatur...
c_lsirgjald43t
Penrose inequality
Summary
Penrose_inequality
This inequality was first proved by Gerhard Huisken and Tom Ilmanen in 1997 in the case where A is the area of the largest component of the outermost minimal surface. Their proof relied on the machinery of weakly defined inverse mean curvature flow, which they developed. In 1999, Hubert Bray gave the first complete pro...
c_q789s4bz4c5i
Bernstein algebra
Summary
Bernstein_problem_in_mathematical_genetics
In mathematical genetics, a genetic algebra is a (possibly non-associative) algebra used to model inheritance in genetics. Some variations of these algebras are called train algebras, special train algebras, gametic algebras, Bernstein algebras, copular algebras, zygotic algebras, and baric algebras (also called weight...
c_qztcsv96vslb
Higman-Sims graph
Summary
Higman-Sims_graph
In mathematical graph theory, the Higman–Sims graph is a 22-regular undirected graph with 100 vertices and 1100 edges. It is the unique strongly regular graph srg(100,22,0,6), where no neighboring pair of vertices share a common neighbor and each non-neighboring pair of vertices share six common neighbors. It was first...
c_n1nvd2wbi5o0
3-transposition group
Summary
3-transposition_group
In mathematical group theory, a 3-transposition group is a group generated by a conjugacy class of involutions, called the 3-transpositions, such that the product of any two involutions from the conjugacy class has order at most 3. They were first studied by Bernd Fischer (1964, 1970, 1971) who discovered the three Fis...
c_vevaozxmv6ym
C-group
Summary
C-group
In mathematical group theory, a C-group is a group such that the centralizer of any involution has a normal Sylow 2-subgroup. They include as special cases CIT-groups where the centralizer of any involution is a 2-group, and TI-groups where any Sylow 2-subgroups have trivial intersection. The simple C-groups were deter...
c_c87kg8n4g9vi
Demushkin group
Summary
Demushkin_group
In mathematical group theory, a Demushkin group (also written as Demuškin or Demuskin) is a pro-p group G having a certain properties relating to duality in group cohomology. More precisely, G must be such that the first cohomology group with coefficients in Fp = Z/p Z has finite rank, the second cohomology group has r...
c_exnt22hj9qiu
Normal p-complement
Summary
P-nilpotent_group
In mathematical group theory, a normal p-complement of a finite group for a prime p is a normal subgroup of order coprime to p and index a power of p. In other words the group is a semidirect product of the normal p-complement and any Sylow p-subgroup. A group is called p-nilpotent if it has a normal p-complement.
c_ppjvpsbonm83
Special abelian subgroup
Summary
Special_abelian_subgroup
In mathematical group theory, a subgroup of a group is termed a special abelian subgroup or SA-subgroup if the centralizer of any nonidentity element in the subgroup is precisely the subgroup(Curtis & Reiner 1981, p.354). Equivalently, an SA subgroup is a centrally closed abelian subgroup. Any SA subgroup is a maximal ...
c_k9515ivgpvy5
Tame group
Summary
Tame_group
In mathematical group theory, a tame group is a certain kind of group defined in model theory. Formally, we define a bad field as a structure of the form (K, T), where K is an algebraically closed field and T is an infinite, proper, distinguished subgroup of K, such that (K, T) is of finite Morley rank in its full lang...
c_rvclinxpsdcw
Hall–Higman theorem
Summary
Hall–Higman_theorem
In mathematical group theory, the Hall–Higman theorem, due to Philip Hall and Graham Higman (1956, Theorem B), describes the possibilities for the minimal polynomial of an element of prime power order for a representation of a p-solvable group.
c_fis02p4wqglx
Schur cover
Summary
Schur_multiplier
In mathematical group theory, the Schur multiplier or Schur multiplicator is the second homology group H 2 ( G , Z ) {\displaystyle H_{2}(G,\mathbb {Z} )} of a group G. It was introduced by Issai Schur (1904) in his work on projective representations.
c_pjehhdga13xl
Automorphism group of a free group
Summary
Automorphism_group_of_a_free_group
In mathematical group theory, the automorphism group of a free group is a discrete group of automorphisms of a free group. The quotient by the inner automorphisms is the outer automorphism group of a free group, which is similar in some ways to the mapping class group of a surface.
c_gfo6ooudq94p
Balance theorem
Summary
Balance_theorem
In mathematical group theory, the balance theorem states that if G is a group with no core then G either has disconnected Sylow 2-subgroups or it is of characteristic 2 type or it is of component type (Gorenstein 1983, p. 7). The significance of this theorem is that it splits the classification of finite simple groups ...
c_5nd6rbtrxlby
Root data
Summary
Root_datum
In mathematical group theory, the root datum of a connected split reductive algebraic group over a field is a generalization of a root system that determines the group up to isomorphism. They were introduced by Michel Demazure in SGA III, published in 1970.
c_nkwvo4tkbocr
Green's function number
Summary
Green's_function_number
In mathematical heat conduction, the Green's function number is used to uniquely categorize certain fundamental solutions of the heat equation to make existing solutions easier to identify, store, and retrieve.
c_gx60uskl35uh
Perpetuant
Summary
Perpetuant
In mathematical invariant theory, a perpetuant is informally an irreducible covariant of a form or infinite degree. More precisely, the dimension of the space of irreducible covariants of given degree and weight for a binary form stabilizes provided the degree of the form is larger than the weight of the covariant, and...
c_mq3j531oid1j
Perpetuant
Summary
Perpetuant
Elliott (1907) describes the early history of perpetuants and gives an annotated bibliography. MacMahon conjectured and Stroh proved that the dimension of the space of perpetuants of degree n>2 and weight w is the coefficient of xw of x 2 n − 1 − 1 ( 1 − x 2 ) ( 1 − x 3 ) ⋯ ( 1 − x n ) {\displaystyle {\frac {x^{2^{n-1}...
c_a2ltk9yo1rrm
Transvectant
Summary
Transvectant
In mathematical invariant theory, a transvectant is an invariant formed from n invariants in n variables using Cayley's Ω process.
c_7kdx9ojzebg7
Evectant
Summary
Evectant
In mathematical invariant theory, an evectant is a contravariant constructed from an invariant by acting on it with a differential operator called an evector. Evectants and evectors were introduced by Sylvester (1854, p.95).
c_tjsfo7g8ztzm
Invariant of a binary form
Summary
Invariants_of_binary_form
In mathematical invariant theory, an invariant of a binary form is a polynomial in the coefficients of a binary form in two variables x and y that remains invariant under the special linear group acting on the variables x and y.
c_8uaognnplxym
Canonizant
Summary
Canonizant
In mathematical invariant theory, the canonizant or canonisant is a covariant of forms related to a canonical form for them.
c_mw1d7w456sqx
Catalecticant
Summary
Catalecticant
In mathematical invariant theory, the catalecticant of a form of even degree is a polynomial in its coefficients that vanishes when the form is a sum of an unusually small number of powers of linear forms. It was introduced by Sylvester (1852); see Miller (2010). The word catalectic refers to an incomplete line of vers...
c_pry42kdmesja
Osculant
Summary
Osculant
In mathematical invariant theory, the osculant or tacinvariant or tact invariant is an invariant of a hypersurface that vanishes if the hypersurface touches itself, or an invariant of several hypersurfaces that osculate, meaning that they have a common point where they meet to unusually high order.
c_hdn6e4ykd1f2
74 knot
Summary
74_knot
In mathematical knot theory, 74 is the name of a 7-crossing knot which can be visually depicted in a highly-symmetric form, and so appears in the symbolism and/or artistic ornamentation of various cultures.
c_y4yzmru03fp6
Conway sphere
Summary
Conway_sphere
In mathematical knot theory, a Conway sphere, named after John Horton Conway, is a 2-sphere intersecting a given knot or link in a 3-manifold transversely in four points. In a knot diagram, a Conway sphere can be represented by a simple closed curve crossing four points of the knot, the cross-section of the sphere; suc...
c_l5bcz1hcs78g
Link (knot theory)
Summary
Link_(knot_theory)
In mathematical knot theory, a link is a collection of knots which do not intersect, but which may be linked (or knotted) together. A knot can be described as a link with one component. Links and knots are studied in a branch of mathematics called knot theory. Implicit in this definition is that there is a trivial refe...
c_53y99gt7o86j
Link (knot theory)
Summary
Link_(knot_theory)
For example, a co-dimension 2 link in 3-dimensional space is a subspace of 3-dimensional Euclidean space (or often the 3-sphere) whose connected components are homeomorphic to circles. The simplest nontrivial example of a link with more than one component is called the Hopf link, which consists of two circles (or unkno...
c_ogips1fqd5mb
Hopf link
Summary
Hopf_link
In mathematical knot theory, the Hopf link is the simplest nontrivial link with more than one component. It consists of two circles linked together exactly once, and is named after Heinz Hopf.
c_q71ykl3gofzh
Equisatisfiability
Summary
Equisatisfiability
In mathematical logic (a subtopic within the field of formal logic), two formulae are equisatisfiable if the first formula is satisfiable whenever the second is and vice versa; in other words, either both formulae are satisfiable or both are not. Equisatisfiable formulae may disagree, however, for a particular choice o...
c_vrkl2kut5feg
Equisatisfiability
Summary
Equisatisfiability
Whereas within equisatisfiable formulae, only the primitive proposition the formula imposes is valued. Equisatisfiability is generally used in the context of translating formulae, so that one can define a translation to be correct if the original and resulting formulae are equisatisfiable. Examples of translations invo...
c_ernahugexvqf
Valuation (logic)
Mathematical logic
Valuation_(logic) > Mathematical logic
In mathematical logic (especially model theory), a valuation is an assignment of truth values to formal sentences that follows a truth schema. Valuations are also called truth assignments. In propositional logic, there are no quantifiers, and formulas are built from propositional variables using logical connectives.
c_2vni3jgt2pdu
Valuation (logic)
Mathematical logic
Valuation_(logic) > Mathematical logic
In this context, a valuation begins with an assignment of a truth value to each propositional variable. This assignment can be uniquely extended to an assignment of truth values to all propositional formulas. In first-order logic, a language consists of a collection of constant symbols, a collection of function symbols...
c_i2mz1cwtjw96
Valuation (logic)
Mathematical logic
Valuation_(logic) > Mathematical logic
Formulas are built out of atomic formulas using logical connectives and quantifiers. A structure consists of a set (domain of discourse) that determines the range of the quantifiers, along with interpretations of the constant, function, and relation symbols in the language. Corresponding to each structure is a unique t...
c_fzrmhkzdb9nu
Resolution inference
Summary
First-order_resolution
In mathematical logic and automated theorem proving, resolution is a rule of inference leading to a refutation complete theorem-proving technique for sentences in propositional logic and first-order logic. For propositional logic, systematically applying the resolution rule acts as a decision procedure for formula unsa...
c_kw6bfezbgqeq
Summary
Turnstile_(symbol)
In mathematical logic and computer science the symbol ⊢ ( ⊢ {\displaystyle \vdash } ) has taken the name turnstile because of its resemblance to a typical turnstile if viewed from above. It is also referred to as tee and is often read as "yields", "proves", "satisfies" or "entails".
c_elyf3hdf76bu
Gabbay's separation theorem
Summary
Gabbay's_separation_theorem
In mathematical logic and computer science, Gabbay's separation theorem, named after Dov Gabbay, states that any arbitrary temporal logic formula can be rewritten in a logically equivalent "past → future" form. I.e. the future becomes what must be satisfied. This form can be used as execution rules; a MetateM program i...
c_118525g6llis
Mu-recursive function
Summary
Mu-recursive_function
In mathematical logic and computer science, a general recursive function, partial recursive function, or μ-recursive function is a partial function from natural numbers to natural numbers that is "computable" in an intuitive sense – as well as in a formal one. If the function is total, it is also called a total recursi...
c_yw3mbukrfglv
Mu-recursive function
Summary
Mu-recursive_function
However, not every total recursive function is a primitive recursive function—the most famous example is the Ackermann function. Other equivalent classes of functions are the functions of lambda calculus and the functions that can be computed by Markov algorithms. The subset of all total recursive functions with values...
c_8cgw3qvm2pxp
Univalence axiom
Summary
Higher_inductive_type
In mathematical logic and computer science, homotopy type theory (HoTT ) refers to various lines of development of intuitionistic type theory, based on the interpretation of types as objects to which the intuition of (abstract) homotopy theory applies. This includes, among other lines of work, the construction of homot...
c_kqnqpt1xgj7k
Univalence axiom
Summary
Higher_inductive_type
Although neither is precisely delineated, and the terms are sometimes used interchangeably, the choice of usage also sometimes corresponds to differences in viewpoint and emphasis. As such, this article may not represent the views of all researchers in the fields equally. This kind of variability is unavoidable when a ...
c_pgwr14muxwi5
Top type
Summary
Top_type
In mathematical logic and computer science, some type theories and type systems include a top type that is commonly denoted with top or the symbol ⊤. The top type is sometimes called also universal type, or universal supertype as all other types in the type system of interest are subtypes of it, and in most cases, it c...
c_5xuxzguq6qba
Kleene star
Summary
Kleene_star
In mathematical logic and computer science, the Kleene star (or Kleene operator or Kleene closure) is a unary operation, either on sets of strings or on sets of symbols or characters. In mathematics, it is more commonly known as the free monoid construction. The application of the Kleene star to a set V {\displaystyle ...
c_7v9pxc0djz0i
Kleene star
Summary
Kleene_star
If V {\displaystyle V} is a set of strings, then V ∗ {\displaystyle V^{*}} is defined as the smallest superset of V {\displaystyle V} that contains the empty string ε {\displaystyle \varepsilon } and is closed under the string concatenation operation. If V {\displaystyle V} is a set of symbols or characters, then V ∗ {...
c_g7wdu4a6wexk
Calculus of Constructions
Summary
Calculus_of_Inductive_Constructions
In mathematical logic and computer science, the calculus of constructions (CoC) is a type theory created by Thierry Coquand. It can serve as both a typed programming language and as constructive foundation for mathematics. For this second reason, the CoC and its variants have been the basis for Coq and other proof assi...
c_c7m22j7nswnm
Lambda-mu calculus
Summary
Lambda-mu_calculus
In mathematical logic and computer science, the lambda-mu calculus is an extension of the lambda calculus introduced by M. Parigot. It introduces two new operators: the μ operator (which is completely different both from the μ operator found in computability theory and from the μ operator of modal μ-calculus) and the b...
c_uui5zih03bff
Lambda-mu calculus
Summary
Lambda-mu_calculus
According to the Curry–Howard isomorphism, lambda calculus on its own can express theorems in intuitionistic logic only, and several classical logical theorems can't be written at all. However with these new operators one is able to write terms that have the type of, for example, Peirce's law. Semantically these operat...
c_k3b44wxsv67t
Two-variable logic with counting
Summary
Two-variable_logic_with_counting
In mathematical logic and computer science, two-variable logic is the fragment of first-order logic where formulae can be written using only two different variables. This fragment is usually studied without function symbols.
c_yrkc2q2o60to
Analytical hierarchy
Summary
Analytical_hierarchy
In mathematical logic and descriptive set theory, the analytical hierarchy is an extension of the arithmetical hierarchy. The analytical hierarchy of formulas includes formulas in the language of second-order arithmetic, which can have quantifiers over both the set of natural numbers, N {\displaystyle \mathbb {N} } , a...
c_ws5ljpkjxpvp
Implication graph
Summary
Implication_graph
In mathematical logic and graph theory, an implication graph is a skew-symmetric, directed graph G = (V, E) composed of vertex set V and directed edge set E. Each vertex in V represents the truth status of a Boolean literal, and each directed edge from vertex u to vertex v represents the material implication "If the li...
c_w8b47n4kr7nx
Potential isomorphism
Summary
Potential_isomorphism
In mathematical logic and in particular in model theory, a potential isomorphism is a collection of finite partial isomorphisms between two models which satisfies certain closure conditions. Existence of a partial isomorphism entails elementary equivalence, however the converse is not generally true, but it holds for ω...
c_mz23ddu2plqu
Universal Horn theory
Summary
Universal_Horn_theory
In mathematical logic and logic programming, a Horn clause is a logical formula of a particular rule-like form which gives it useful properties for use in logic programming, formal specification, and model theory. Horn clauses are named for the logician Alfred Horn, who first pointed out their significance in 1951.
c_96qtjxzbzzmi
Completeness (logic)
Summary
Completeness_(logic)
In mathematical logic and metalogic, a formal system is called complete with respect to a particular property if every formula having the property can be derived using that system, i.e. is one of its theorems; otherwise the system is said to be incomplete. The term "complete" is also used without qualification, with di...
c_7uj5b2om3zdn
Skolem paradox
Summary
Skolem_paradox
In mathematical logic and philosophy, Skolem's paradox is a seeming contradiction that arises from the downward Löwenheim–Skolem theorem. Thoralf Skolem (1922) was the first to discuss the seemingly contradictory aspects of the theorem, and to discover the relativity of set-theoretic notions now known as non-absolutene...
c_s33uvyqvvl6v
Skolem paradox
Summary
Skolem_paradox
295). Skolem's paradox is that every countable axiomatisation of set theory in first-order logic, if it is consistent, has a model that is countable. This appears contradictory because it is possible to prove, from those same axioms, a sentence that intuitively says (or that precisely says in the standard model of the ...
c_5a834ri7i3zu
Skolem paradox
Summary
Skolem_paradox
Thus the seeming contradiction is that a model that is itself countable, and which therefore contains only countable sets, satisfies the first-order sentence that intuitively states "there are uncountable sets". A mathematical explanation of the paradox, showing that it is not a contradiction in mathematics, was given ...
c_wsi6kh0nb6hy
Skolem paradox
Summary
Skolem_paradox
The philosophical implications of Skolem's paradox have received much study. One line of inquiry questions whether it is accurate to claim that any first-order sentence actually states "there are uncountable sets". This line of thought can be extended to question whether any set is uncountable in an absolute sense. Mor...
c_w3u21j6y48d8
Collapsing function
Summary
Collapsing_function
In mathematical logic and set theory, an ordinal collapsing function (or projection function) is a technique for defining (notations for) certain recursive large countable ordinals, whose principle is to give names to certain ordinals much larger than the one being defined, perhaps even large cardinals (though they can...
c_dd90lo24zrkl
Collapsing function
Summary
Collapsing_function
An example of how this works will be detailed below, for an ordinal collapsing function defining the Bachmann–Howard ordinal (i.e., defining a system of notations up to the Bachmann–Howard ordinal). The use and definition of ordinal collapsing functions is inextricably intertwined with the theory of ordinal analysis, s...
c_szisawowvdly
Ordinal notation
Summary
Ordinal_notation
In mathematical logic and set theory, an ordinal notation is a partial function mapping the set of all finite sequences of symbols, themselves members of a finite alphabet, to a countable set of ordinals. A Gödel numbering is a function mapping the set of well-formed formulae (a finite sequence of symbols on which the ...
c_hbsygajvmqvi
Ordinal notation
Summary
Ordinal_notation
A recursive ordinal notation must satisfy the following two additional properties: the subset of natural numbers is a recursive set the induced well-ordering on the subset of natural numbers is a recursive relationThere are many such schemes of ordinal notations, including schemes by Wilhelm Ackermann, Heinz Bachmann, ...
c_yeznq96dv6pp
Ordinal notation
Summary
Ordinal_notation
In many systems, such as Veblen's well known system, the functions are normal functions, that is, they are strictly increasing and continuous in at least one of their arguments, and increasing in other arguments. Another desirable property for such functions is that the value of the function is greater than each of its...
c_twsyd5l85fjp
Minsky machine
Summary
Minsky_machine
In mathematical logic and theoretical computer science, a register machine is a generic class of abstract machines used in a manner similar to a Turing machine. All the models are Turing equivalent.
c_ksi9zdg0mk5x
Convergent term rewriting system
Summary
Abstract_rewriting
In mathematical logic and theoretical computer science, an abstract rewriting system (also (abstract) reduction system or abstract rewrite system; abbreviated ARS) is a formalism that captures the quintessential notion and properties of rewriting systems. In its simplest form, an ARS is simply a set (of "objects") toge...
c_rxcru5fd1jnz
Convergent term rewriting system
Summary
Abstract_rewriting
Historically, there have been several formalizations of rewriting in an abstract setting, each with its idiosyncrasies. This is due in part to the fact that some notions are equivalent, see below in this article. The formalization that is most commonly encountered in monographs and textbooks, and which is generally fol...
c_8uqb63h257ym
Lambda cube
Summary
Lambda_cube
In mathematical logic and type theory, the λ-cube (also written lambda cube) is a framework introduced by Henk Barendregt to investigate the different dimensions in which the calculus of constructions is a generalization of the simply typed λ-calculus. Each dimension of the cube corresponds to a new kind of dependency ...
c_vznrpqueur2c
Lambda cube
Summary
Lambda_cube
y-axis ( ↑ {\displaystyle \uparrow } ): terms that can bind types, corresponding to polymorphism. z-axis ( ↗ {\displaystyle \nearrow } ): types that can bind types, corresponding to (binding) type operators.The different ways to combine these three dimensions yield the 8 vertices of the cube, each corresponding to a di...
c_k1ic5vx9d3hn
Löwenheim number
Summary
Löwenheim_number
In mathematical logic the Löwenheim number of an abstract logic is the smallest cardinal number for which a weak downward Löwenheim–Skolem theorem holds. They are named after Leopold Löwenheim, who proved that these exist for a very broad class of logics.
c_xkesrom7e758
Theory of pure equality
Summary
Theory_of_pure_equality
In mathematical logic the theory of pure equality is a first-order theory. It has a signature consisting of only the equality relation symbol, and includes no non-logical axioms at all.This theory is consistent but incomplete, as a non-empty set with the usual equality relation provides an interpretation making certain...
c_c8nw7ovtlxwy
Beth definability
Summary
Beth_definability
In mathematical logic, Beth definability is a result that connects implicit definability of a property to its explicit definability. Specifically Beth definability states that the two senses of definability are equivalent. First-order logic has the Beth definability property.
c_qkbn0tq4ev3y
Craig interpolation
Summary
Craig_interpolation
In mathematical logic, Craig's interpolation theorem is a result about the relationship between different logical theories. Roughly stated, the theorem says that if a formula φ implies a formula ψ, and the two have at least one atomic variable symbol in common, then there is a formula ρ, called an interpolant, such tha...
c_9cyi99ypd68l
Craig's theorem
Summary
Craig's_theorem
In mathematical logic, Craig's theorem (also known as Craig's trick) states that any recursively enumerable set of well-formed formulas of a first-order language is (primitively) recursively axiomatizable. This result is not related to the well-known Craig interpolation theorem, although both results are named after th...
c_syi6v2dp3b99
Diaconescu theorem
Summary
Diaconescu's_theorem
In mathematical logic, Diaconescu's theorem, or the Goodman–Myhill theorem, states that the full axiom of choice is sufficient to derive the law of the excluded middle or restricted forms of it. The theorem was discovered in 1975 by Radu Diaconescu and later by Goodman and Myhill. Already in 1967, Errett Bishop posed t...
c_r6uc4nhqy2l3
Frege's propositional calculus
Summary
Frege's_propositional_calculus
In mathematical logic, Frege's propositional calculus was the first axiomatization of propositional calculus. It was invented by Gottlob Frege, who also invented predicate calculus, in 1879 as part of his second-order predicate calculus (although Charles Peirce was the first to use the term "second-order" and developed...
c_yvcc2ejrqn1k
Frege's propositional calculus
Summary
Frege's_propositional_calculus
Frege's PC and standard PC share two common axioms: THEN-1 and THEN-2. Notice that axioms THEN-1 through THEN-3 only make use of (and define) the implication operator, whereas axioms FRG-1 through FRG-3 define the negation operator.
c_whljmdm08z2j
Frege's propositional calculus
Summary
Frege's_propositional_calculus
The following theorems will aim to find the remaining nine axioms of standard PC within the "theorem-space" of Frege's PC, showing that the theory of standard PC is contained within the theory of Frege's PC. (A theory, also called here, for figurative purposes, a "theorem-space", is a set of theorems that are a subset ...
c_p0yb2ywqyoer
Kirby–Paris theorem
Summary
Goodstein_sequence
In mathematical logic, Goodstein's theorem is a statement about the natural numbers, proved by Reuben Goodstein in 1944, which states that every Goodstein sequence eventually terminates at 0. Laurence Kirby and Jeff Paris showed that it is unprovable in Peano arithmetic (but it can be proven in stronger systems, such a...
c_2wvmv08b4rl8
Kirby–Paris theorem
Summary
Goodstein_sequence
Kirby and Paris introduced a graph-theoretic hydra game with behavior similar to that of Goodstein sequences: the "Hydra" (named for the mythological multi-headed Hydra of Lerna) is a rooted tree, and a move consists of cutting off one of its "heads" (a branch of the tree), to which the hydra responds by growing a fini...
c_6fyqk4i34ow1
Gödel's β function
Summary
Gödel's_β_function
In mathematical logic, Gödel's β function is a function used to permit quantification over finite sequences of natural numbers in formal theories of arithmetic. The β function is used, in particular, in showing that the class of arithmetically definable functions is closed under primitive recursion, and therefore inclu...
c_hjcrcjvv2os4
Heyting arithmetic
Summary
Heyting_arithmetic
In mathematical logic, Heyting arithmetic H A {\displaystyle {\mathsf {HA}}} is an axiomatization of arithmetic in accordance with the philosophy of intuitionism. It is named after Arend Heyting, who first proposed it.
c_fkx473k7dlud
Lindenbaum's lemma
Summary
Lindenbaum's_lemma
In mathematical logic, Lindenbaum's lemma, named after Adolf Lindenbaum, states that any consistent theory of predicate logic can be extended to a complete consistent theory. The lemma is a special case of the ultrafilter lemma for Boolean algebras, applied to the Lindenbaum algebra of a theory.
c_t2w0hjofc3g2
Lindstrom's theorem
Summary
Lindström's_theorem
In mathematical logic, Lindström's theorem (named after Swedish logician Per Lindström, who published it in 1969) states that first-order logic is the strongest logic (satisfying certain conditions, e.g. closure under classical negation) having both the (countable) compactness property and the (downward) Löwenheim–Skol...
c_m4vahwo0nazg
Löb's Theorem
Summary
Löb's_Theorem
In mathematical logic, Löb's theorem states that in Peano arithmetic (PA) (or any formal system including PA), for any formula P, if it is provable in PA that "if P is provable in PA then P is true", then P is provable in PA. If Prov(P) means that the formula P is provable, we may express this more formally as If P A ⊢...
c_z2iyebfqa7nx
Morley rank
Summary
Morley_rank
In mathematical logic, Morley rank, introduced by Michael D. Morley (1965), is a means of measuring the size of a subset of a model of a theory, generalizing the notion of dimension in algebraic geometry.
c_ldthcj2lr6ii
Typed set theory
Summary
Typed_set_theory
In mathematical logic, New Foundations (NF) is an axiomatic set theory, conceived by Willard Van Orman Quine as a simplification of the theory of types of Principia Mathematica. Quine first proposed NF in a 1937 article titled "New Foundations for Mathematical Logic"; hence the name. Much of this entry discusses NF wit...
c_z0067ijyeq8i
Typed set theory
Summary
Typed_set_theory
New Foundations has a universal set, so it is a non-well-founded set theory. That is to say, it is an axiomatic set theory that allows infinite descending chains of membership, such as ... xn ∈ xn-1 ∈ ... ∈ x2 ∈ x1. It avoids Russell's paradox by permitting only stratifiable formulas to be defined using the axiom schem...
c_5ijy5ppmsw0q
Peano–Russell notation
Summary
Peano–Russell_notation
In mathematical logic, Peano–Russell notation was Bertrand Russell's application of Giuseppe Peano's logical notation to the logical notions of Frege and was used in the writing of Principia Mathematica in collaboration with Alfred North Whitehead: "The notation adopted in the present work is based upon that of Peano, ...
c_pbe6ylg8n1bt
Rosser's trick
Summary
Rosser's_trick
In mathematical logic, Rosser's trick is a method for proving Gödel's incompleteness theorems without the assumption that the theory being considered is ω-consistent (Smorynski 1977, p. 840; Mendelson 1977, p. 160). This method was introduced by J. Barkley Rosser in 1936, as an improvement of Gödel's original proof of ...
c_n8tpkd0xwk1v
Russell paradox
Summary
Russel's_paradox
In mathematical logic, Russell's paradox (also known as Russell's antinomy) is a set-theoretic paradox published by the British philosopher and mathematician Bertrand Russell in 1901. Russell's paradox shows that every set theory that contains an unrestricted comprehension principle leads to contradictions. The paradox...