T2-Separation Axiom
Given any two distinct points 
, there exist neighborhoods 
and 
of 
and 
, respectively, with 
. It then follows that finite Subsets are Closed.
- Delian Problem
- de Longchamps Point
- Del Pezzo Surface
- Delta Amplitude
- Delta Curve
- Delta Function
- Deltahedron
- Delta Sequence
- Delta Variation
- Deltoid
- Deltoidal Hexecontahedron
- Deltoidal Icositetrahedron
- Deltoid Caustic
- Deltoid Evolute
- Deltoid Involute
- Deltoid Pedal Curve
- Deltoid Radial Curve
- de Mere's Problem
- Demlo Number
- de Moivre-Laplace Theorem
- de Moivre Number
- de Moivre's Identity
- de Moivre's Quintic
- de Morgan's and Bertrand's Test
- de Morgan's Duality Law