LTspice .ac analysis - expressions don't work or work inconsistently
An .AC analysis means a small-signal analysis on a circuit that is linearized around its operation point. What you're supplying, that AC 1, is a complex signal of 1 V peak, which would defeat the definition of small-signal, but which works even if it's AC 1k because the whole circuit is linearized.
A division is not linear (B3), so it can't be linearized, yet in the waveform window you can see x/y since that's how you plot the gain, V(out)/V(in). It would not work with signals since what do you do if you have a division by zero, for example? The help will provide more info in LTspice &gt; Waveform Viewer &gt; Waveform Arithmetic, about which functions work and which not. You'll also see re() and im() (along with mag() and ph()) in there, what they do and where.
Regarding min() and max() (this latter one is not shown in the help as a function that's not available, but it's implied since min() is shown), you have to be a bit creative. Simply plot the ratio of the two quantities, say x/y, and when the plot is zero or positive it means x&gt;=y, else x&lt;y.
BTW, freq, frequency, and w are keywords that mean frequency (the first two), and pulsation (w), and can be plotted directly. They can even be used in equations.