Legend for lecture notations

The following are frequently used during lecture:

• Q+A format to establish motivation and narrative Q: What does this mean? A: It means this.
• NB = Nota Bene (take special note)
• EX. = Example
• Note = minor points worthy of bullet list
• Key Point = Something that I seem to have said since time immemorial and is useful to remember
• Idea = I lost track of whether I was in a question dialog but had an idea about whatever we were doing at the moment.

Mathematical Abbreviations

• s.t. = such that

• w.r.t = with respect to

• iff = if and only if

  If and only if - Wikipedia

Mathematical Notations

• The variable exists in the set of real numbers, i.e., its a decimal.

$$ x \in \mathbb{R} = (-\infty, \infty) $$

• Positive real numbers (including zero)

$$ x \in \mathbb{R}^{+}_{0} = [0,\infty) $$

• Positive real number (excluding zero)

$$ x \in \mathbb{R}^{+} = (0,\infty) $$

• The variable is in the complex number system