# New in *MathWorld* -- January
2021

### Friday January 22, 2021

- Radio Number (modified)

### Tuesday January 12, 2021

- Radio Labeling (modified)

### Monday January 11, 2021

- Radio Labeling
- Radio Number (modified)

### Thursday January 7, 2021

### Monday January 4, 2021

- Braced Polygon (modified)
- Laman Graph (modified)
- Null Space (modified)

### Sunday January 3, 2021

- Braced Polygon (modified)
- Hochberg-O'Donnell Fish Graph (modified)
- Positive Definite Matrix (modified)

### Saturday January 2, 2021

- Antihermitian Matrix (modified)
- AntihermitianMatrixQ
- Antimetric Matrix
- Antisymmetric Matrix (modified)
- AntisymmetricMatrixQ
- Asymmetric Matrix
- Diagonalizable Matrix (modified)
- DiagonalizableMatrixQ
- Diagonal Matrix (modified)
- DiagonalMatrixQ
- Hermitian Matrix (modified)
- HermitianMatrixQ
- Indefinite Matrix (modified)
- IndefiniteMatrixQ
- Lower Triangular Matrix (modified)
- LowerTriangularMatrixQ
- Negative Definite Matrix (modified)
- NegativeDefiniteMatrixQ
- Negative Semidefinite Matrix (modified)
- NegativeSemidefiniteMatrixQ
- Normal Matrix (modified)
- NormalMatrixQ
- Orthogonal Matrix (modified)
- OrthogonalMatrixQ
- Positive Definite Matrix (modified)
- PositiveDefiniteMatrixQ
- Positive Semidefinite Matrix (modified)
- PositiveSemidefiniteMatrixQ
- Square Matrix (modified)
- SquareMatrixQ
- Symmetric Matrix (modified)
- SymmetricMatrixQ
- Unitary Matrix (modified)
- UnitaryMatrixQ
- Upper Triangular Matrix (modified)
- UpperTriangularMatrixQ

### Friday January 1, 2021

- Corona Graph Product
- Graph Cube (modified)
- Graph Square (modified)

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