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 title: Matrix calculus
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+  # beamer: default
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+    text: PDF
+  # - format: beamer
+  #   text: Slides
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 ## Basic linear algebra background
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 ### Vectors and matrices
 
 We will treat all vectors as column vectors by default. The space of real vectors of length $n$ is denoted by $\mathbb{R}^n$, while the space of real-valued $m \times n$ matrices is denoted by $\mathbb{R}^{m \times n}$. That's it: [^1]