SU-SOC175 JAN142025
Last edited: January 1, 2026Key Insights
- Does China have a modern form of government?
- China’s National Government as a Hierarchy: is it centralized? Meritocratic?
Forms of Government
- Modern Government Model (“European Model”—Enlightenment English/Scottish/French): state should adjudicate interests in a fair and legitimate fashion
- US Government Model: hybrid, constitutional, late 18th entry design (i.e. “government is designed to stop things”)
- Alternative Model (“Developer Model”): State’s purpose is to push national progress through economic and military strength (i.e. “the government pushes things forward)
- China
- Axis Powers
Modern Government
We typical define a modern government as a liberal democratic government. But China’s system is in some sense much newer than liberal democracy—invented by the Soviets.
Words to Concepts
Last edited: January 1, 2026Chen’s Talk.
constructive convexity verification
Last edited: January 1, 2026- start with function \(f\) gives as expression
- build parse tree for expression (leaves and variables / constants, nodes are functions of child expressions)
- apply general composition rule that preserve convexity
Greedy parses may fail, such as in the case of logsumexp.
Euclidian Geometry Crash Course
Last edited: January 1, 2026line
All points of the form \(x = \theta x_{1} + \qty(1-\theta) x_{2}\), with \(\theta \in \mathbb{R}\) is a “line through \(x_1\), \(x_2\)”.
affine set
For set \(G\), for all two points \(x_1, x_2 \in G\), all points lying on the line \(x_1, x_2 \in G\). For instance, the solution set of a set of linear equations \(\qty {x \mid A x = b}\).
convex set
line segment
all points form \(x = \theta x_{1} + \qty(1-\theta)x_{2}\), with \(0 \leq \theta \leq 1\).
expectation maximization
Last edited: January 1, 2026Sorta like “distribution-based k-means clustering”. guarantees convergence (i.e. each parameter will converge to the maximum possible parameter).
constituents
requirements
Two steps:
e-step
“guess the value of \(z^{(i)}\); soft guesses of cluster assignments”
\begin{align} w_{j}^{(i)} &= p\qty(z^{(i)} = j | x^{(i)} ; \phi, \mu, \Sigma) \\ &= \frac{p\qty(x^{(i)} | z^{(i)}=j) p\qty(z^{(i)}=j))}{\sum_{l=1}^{k}p\qty(x^{(i)} | z^{(i)}=l) p\qty(z^{(i)}=l))} \end{align}
Where we have:
- \(p\qty(x^{(i)} |z^{(i)}=j)\) from the Gaussian distribution, where we have \(\Sigma_{j}\) and \(\mu_{j}\) for the parameters of our Gaussian \(j\).
- \(p\qty(z^{(i)} =j)\) is just \(\phi_{j}\) which we are learning
These weights \(w_{j}\) are how much the model believes it belongs to each cluster.
