Table of Contents
Definitions
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Span:
Span: of a set of vectors is the set of all linear combinations of the vectors; \(\text{span}(v_1,\ldots,v_d) = \sum_{i=0}^d \lambda_iv_i : \lambda \in \mathbb{R}^d\) -
Linear Independence:
- Subspace:
- Definition:
- Geometrical Interpretation:
- Mathematical Representation:
- Affine Sets and Subspaces (Cosets - Abstract Algebra):
- Definition:
- Geometrical Interpretation:
- Mathematical Representation:
- Special Case of a single basis vector:
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Find the Affine Subspace Corresponding to the following set:
The set \(\boldsymbol{L}\) in \(\mathbb{R}^3\) defined by:
\(x_{1}-13 x_{2}+4 x_{3}=2, \quad 3 x_{2}-x_{3}=9\)
\(5x_{1}-8x_{2}+17 x_{3}=2, \quad 6 x_{2}-2x_{3}=13\) - Mathematical Representation of a line:
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Basis:
- Dimension:
Norms and Scalar Products
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Scalar/Inner/Dot Product:
- Norms:
- Definition + Theorem (properties):
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\(l_p\) Norms:
- The \(l_1-norm\):
- (Geometrically) Corresponds to:
- The \(l_2-norm\) (Euclidean Norm):
- (Geometrically) Corresponds to:
- Properties:
- The \(l_\infty-norm\):
- (Geometrically) Corresponds to:
- Application:
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The Cardinality:
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Cauchy-Schwartz inequality:
- Angles between vectors:
Orthogonality
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Orthogonal Vectors:
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Orthogonal Matrix:
Projections
- Line:
- Definition:
- Mathematical Representation:
- Projection on a line:
- Set up Equation:
- The Projection:
- Solve Equation:
- Interpreting the scalar product:
Hyperplanes
- Hyperplanes:
- Two definitions:
- Hyper-Planes as Affine Sets:
- How are they useful?:
- Geometry of Hyperplanes:
Half-Spaces
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Half-Space:
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Geometric Interptation:
Linear Functions and Transformations, and Maps
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Linear Functions:
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Affine Functions:
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Equivalent Definitions of Linear Functions [Theorem]:
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Vector Form (and the scalar product):
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Gradient of a Linear Function:
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Gradient of an Affine Function:
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Interpreting \(a\) and \(b\):
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First-order approximation of non-linear functions:
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First-order Expansion of a function [Theorem]:
Matrices
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Matrix Transpose:
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Matrix-vector product:
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Left Product:
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Matrix-matrix product:
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Block Matrix Products:
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Outer Products:
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Trace:
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Scalar Product:
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Special Matrices:
Matrix Norms
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Norm:
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\(l_{p,q}\) norms:
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\(l_{2,2}\) (Frobenius norm):
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\(l_{\infty,\infty}\) (Max Norm):
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The Spectral Norm:{: .bodyContents9 #bodyContents95
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Asynchronous:
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Asynchronous:
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Equivalence of Norms:
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Applications: