netweaver:nodes:subtraction-negation

The subtraction / negation node either takes the difference of the values of its two child-nodes or returns the negation of its single child-node.

- Minimum number of child-nodes: 1
- Maximum number of child-nodes: 2

if number of child-nodes = 1 then value = -value_{1}

if number of child-nodes = 2 then value = value_{1} - value_{2}