how is the minus sign understood in set theory, is it similar to the complement (\) function. Assume:
$A = \{1,2,3\},$
$B = \{2,3,4\}$
Is $A - B = \{1\}$, or is it $\{1\}$ plus the piece of $\{4\}$ that you 'owe', assuming in Venn Diagram you are subtracting a piece of $B$ from $A$ itself that do not contain the element '4'. (Is it fair to visualise sets in Venn Diagrams?)
Or do we just equate the minus($-$) sign to the complement() function.

$A-B$ is alternative notation for $A \setminus B$. They both mean the elements that are in $A$ but not in $B$.
