I have been introduced to the Feynman diagrams in QFT after following Wick-Dyson tedious formalism.
Two things are unclear, though, about the Feynman shortcut to compute scattering amplitudes.
What are the horizontal and vertical axes in these diagrams? Are they $x$ and $t$ respectively or $x$ and $y$?
If yes then we are drawing a particle with an exact momentun $p$.
But doesn't this violate the uncertainty principle since we are assuming exactly measured $x$ and $p$?