_index.org

convexity preserve line restriction

Last edited: January 1, 2026

\(f: \mathbb{R}^{n} \to \mathbb{R}\) is convex IFF the function \(g: \mathbb{R} \to \mathbb{R}\) is convex:

\begin{equation} g\qty(t) = f\qty(x + tv), \text{dom } g = \qty {t \mid x + tv \in \text{dom }f} \end{equation}

is convex in \(t \in \mathbb{R}\) for any \(x \in \text{dom } f\), \(v \in \mathbb{R}^{n}\).

log determinant

Last edited: January 1, 2026

\begin{equation} f\qty(X) = \log \text{det} X \end{equation}

seperating hyperplane theorem

Last edited: January 1, 2026

IF \(C\) and \(D\) are non-empty disjoint \(C \cap D = \emptyset\), and \(C\) and \(D\) are convex sets, \(\exists a \neq 0\) such that:

\begin{equation} a^{T} x \leq b, x \in C \end{equation}

\begin{equation} a^{T}x \geq b, x \in D \end{equation}

The hyperplane:

\begin{equation} \qty {x \mid a^{T} x = b} \end{equation}

separates \(C, D\) such that \(a^{T}x \geq b, a^{T}x \leq b\).

SU-EE364a JAN062026

Last edited: January 1, 2026

Key Sequence

Notation

New Concepts

Important Results / Claims

Questions

Interesting Factoids