Concave
A Set in 
is concave if it does not contain all the Line Segments connecting anypair of its points. If the Set does contain all the Line Segments, it is calledConvex.
- Dirichlet Fourier Series Conditions
- Dirichlet Function
- Dirichlet Integrals
- Dirichlet Kernel
- Dirichlet Lambda Function
- Dirichlet L-Series
- Dirichlet Region
- Dirichlet's Boxing-In Principle
- Dirichlet's Box Principle
- Dirichlet Series
- Dirichlet's Formula
- Dirichlet's Lemma
- Dirichlet's Principle
- Dirichlet's Test
- Dirichlet's Theorem
- Dirichlet Structure Constant
- Dirichlet Tessellation
- Dirty Beam
- Dirty Map
- Disc
- Disconnected Form
- Disconnectivity
- Discontinuity
- Discontinuous
- Discordant Permutation