# Category:Explanation Required

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This category is for pages which have a point which needs explaining.

See the Explain template.

## Pages in category "Explanation Required"

The following 200 pages are in this category, out of 761 total.

(previous page) (next page)### A

- Abel's Theorem
- Abel's Theorem/Historical Note
- Accumulation Point of Infinite Sequence in First-Countable Space is Subsequential Limit
- Achilles and the Tortoise
- Definition:Addition of Polynomials
- Definition:Addition of Polynomials/Polynomial Forms
- Definition:Aleph Hypothesis
- Aleph is Infinite Cardinal
- Definition:Aleph Mapping
- Alexander's Compactness Theorem
- Definition:Algebra (Abstract Algebra)
- Algebraic Element of Field Extension is Root of Unique Monic Polynomial of Minimal Degree
- Alternating Sum and Difference of Binomial Coefficients for Given n
- Alternating Sum and Difference of Binomial Coefficients for Given n/Proof 1
- Analytic Continuation of Dirichlet L-Function
- Approximation to Reciprocal times Derivative of Gamma Function
- Definition:Archimedean Property
- Definition:Archimedean Property/Norm
- Arens-Fort Space is not Locally Connected
- Definition:Argument (Complex Analysis)
- Artin's Theorem on Alternative Algebras
- Atlas Belongs to Unique Differentiable Structure
- Automorphism Group of C Over R
- Ax-Grothendieck Theorem
- Axiom:Axiom of Choice for Finite Sets
- Axiom:Axiom of Choice for Finite Sets/Proof from Hall's Marriage Theorem
- Axiom of Choice Implies Zorn's Lemma
- Axiom of Choice Implies Zorn's Lemma/Proof 2
- Axiom:Axiom of Continuity
- Axiom:Axiom of Empty Set
- Axiom:Axiom of Infinity/NBG
- Axiom:Axiom of Union/Morse-Kelley

### B

- Baire-Osgood Theorem
- Banach-Steinhaus Theorem
- Barbier's Theorem
- Definition:Barrier
- Basel Problem
- Basel Problem/Proof 2
- Basis for Open Ordinal Topology
- Basis of Free Module is No Greater than Generator
- Bendixson-Dulac Theorem
- Bertrand's Theorem
- Definition:Big-Omega
- Definition:Bilinear Form
- Definition:Bilinear Functional
- Boolean Prime Ideal Theorem
- Borel-Carathéodory Lemma
- Definition:Bounded Below Set/Real Numbers
- Bounded Function is of Exponential Order Zero
- Bourbaki-Witt Fixed Point Theorem
- Branch of Finite Tree is Finite

### C

- Canonical Injection into Cartesian Product of Modules
- Canonical Order Well-Orders Ordered Pairs of Ordinals
- Definition:Cantor Normal Form
- Cantor Set is Uncountable
- Cantor Set is Uncountable/Proof 1
- Cantor Space is Nowhere Dense
- Cantor Space is Nowhere Dense/Proof 1
- Cantor-Bernstein-Schröder Theorem
- Cantor-Bernstein-Schröder Theorem/Proof 1
- Carathéodory's Theorem (Analysis)
- Carathéodory's Theorem (Convex Analysis)
- Definition:Card Game with Bluffing
- Cardinal Number is Ordinal
- Cardinal Number Less than Ordinal
- Cardinality of Infinite Union of Infinite Sets
- Carroll Paradox
- Cartesian Product is Small
- Cartesian Product of Countable Sets is Countable/Corollary
- Cartesian Product of Countable Sets is Countable/Corollary/Proof 1
- Definition:Cartesian Product/Family of Sets/Axiom of Choice
- Cauchy Integral Formula
- Cauchy Mean Value Theorem
- Cauchy Mean Value Theorem/Geometrical Interpretation
- Cauchy-Goursat Theorem
- Cauchy-Hadamard Theorem
- Cauchy-Riemann Equations
- Cauchy-Riemann Equations/Sufficient Condition
- Cayley-Hamilton Theorem
- Cayley-Menger Determinant
- Definition:Center (Abstract Algebra)
- Definition:Center (Abstract Algebra)/Ring
- Central Field is Field of Functional
- Central Limit Theorem
- Cesàro Mean
- Change of Coordinate Vectors Under Linear Transformation
- Definition:Character (Number Theory)
- Character of Representations over C are Algebraic Integers
- Characterisation of Jacobson Radical
- Characterisation of Linearly Independent Set through Free Module Indexed by Set
- Characterisation of Local Rings
- Characterisation of Non-Archimedean Absolute Values
- Characterisation of Totally Ordered Fields
- Characteristic of Increasing Mapping from Toset to Order Complete Toset
- Characteristics of Floor and Ceiling Function
- Characterization of Measures
- Chinese Remainder Theorem (Commutative Algebra)
- Class Equality is Reflexive
- Class Equality is Transitive
- Classical Probability is Probability Measure
- Classification of Compact One-Manifolds
- Classification of Compact Two-Manifolds
- Closed Linear Subspaces Closed under Setwise Addition
- Closed Real Interval is Neighborhood Except at Endpoints
- Closed Unit Interval is not Countably Infinite Union of Disjoint Closed Sets
- Closure Condition for Hausdorff Space
- Closure in Double Pointed Topology
- CNF Satisfiability Problem is NP-Complete
- Definition:Cofinal Ordinal
- Common Section of Bisecting Planes of Cube Bisect and are Bisected by Diagonal of Cube
- Commutative Linear Transformation is G-Module Homomorphism
- Commutativity of Incidence Matrix with its Transpose for Symmetric Design
- Compact Hausdorff Topology is Maximally Compact
- Compact Hausdorff Topology is Minimal Hausdorff
- Compact Subspace of Linearly Ordered Space
- Compact Subspace of Linearly Ordered Space/Reverse Implication
- Compact Subspace of Linearly Ordered Space/Reverse Implication/Proof 2
- Compactness Properties Preserved under Continuous Surjection
- Compatibility of Atlases is Equivalence Relation
- Complete and Totally Bounded Metric Space is Sequentially Compact
- Complete and Totally Bounded Metric Space is Sequentially Compact/Proof 1
- Definition:Complete Ritz Sequence
- Completion Theorem (Metric Space)/Lemma 4
- Complex Numbers as External Direct Product
- Condition for Agreement of Family of Mappings
- Condition for Cofinal Nonlimit Ordinals
- Condition for Composition Series
- Condition for Differentiable Functional to have Extremum
- Condition for Injective Mapping on Ordinals
- Condition for Set Union Equivalent to Associated Cardinal Number
- Conditions for C^1 Smooth Solution of Euler's Equation to have Second Derivative
- Conditions for Extremal Embedding in Field of Functional
- Conditions for Function to be First Integral of Euler's Equations for Vanishing Variation/Corollary 2
- Definition:Conjugate Point
- Connected Subspace of Linearly Ordered Space
- Construction of Inverse Completion/Quotient Mapping/Image of Cancellable Elements
- Content of Scalar Multiple
- Definition:Continued Fraction
- Definition:Continued Fraction Expansion
- Continued Fraction Expansion of Limit of Simple Infinite Continued Fraction equals Expansion Itself
- Definition:Continued Fraction/Expansion of Real Number
- Definition:Continuous Function (Real Analysis)/One Side
- Continuous Function is Riemann Integrable
- Continuous Functions on Compact Space form Banach Space
- Continuous Image of Connected Space is Connected
- Continuous Image of Connected Space is Connected/Corollary 3
- Continuous Image of Connected Space is Connected/Proof 1
- Definition:Continuous Ordered Set
- Definition:Continuous Total Preordering
- Definition:Continuously Embedded
- Continuum Property
- Continuum Property/Proof 1
- Cook-Levin Theorem
- Correspondence Theorem (Group Theory)
- Countable Compactness is Preserved under Continuous Surjection
- Countable Product of Second-Countable Spaces is Second-Countable
- Countable Stability implies Stability for All Infinite Cardinalities
- Countable Union of Finite Sets is Countable
- Countably Compact Metric Space is Compact
- Countably Compact Metric Space is Compact/Proof 2
- Cover of Interval By Closed Intervals is not Pairwise Disjoint
- Cowen-Engeler Lemma
- Definition:Critical Point
- Cyclicity Condition for Units of Ring of Integers Modulo m

### D

- De Morgan's Laws imply Uniquely Complemented Lattice is Boolean Lattice
- Definition:Decomposable Set
- Dedekind's Theorem
- Definition:Dedekind-MacNeille Completion
- Definite Integral of Uniformly Convergent Series of Continuous Functions
- Definition:Definite Integral/Darboux
- Definition of Polynomial from Polynomial Ring over Sequence
- Dependent Choice for Finite Sets
- Derivation of Hamilton-Jacobi Equation
- Derivative of Hyperbolic Cosecant Function
- Derivative of Hyperbolic Secant Function
- Derivative of Inverse Hyperbolic Cosecant
- Derivative of Inverse Hyperbolic Secant
- Derived Set in T1 Space is Closed
- Diagonal Complement Relation Compatible with Group Operation
- Definition:Diffeomorphism
- Definition:Differential Form
- Definition:Direct Sum of Modules
- Directed Hamilton Cycle Problem is NP-complete
- Definition:Dirichlet Character
- Definition:Dirichlet L-function
- Dirichlet L-Function from Trivial Character
- Dirichlet's Test for Uniform Convergence
- Dirichlet's Theorem on Arithmetic Progressions
- Dirichlet's Theorem on Arithmetic Progressions/Lemma 2
- Help:Disambiguation
- Definition:Discrete Probability Measure
- Disjoint Compact Sets in Hausdorff Space have Disjoint Neighborhoods
- Disjoint Compact Sets in Hausdorff Space have Disjoint Neighborhoods/Lemma
- Definition:Disjoint Union (Set Theory)
- Divergent Sequences may be Bounded/Proof 2
- Divided by Positive Element of Quotient Field
- Domain of Small Relation is Small
- Dominated Strategy may be Optimal
- Definition:Dual Isomorphism (Order Theory)