Does the fact that a sentence is an universal sentence (i.e. x+y=y+z) automatically make all variables bound?
Let me give you an example. In the expression "for any x, x-y=x+(-y)" is only an x variable bound or both x & y are bound variables?
MY doubt is due to the convention that in many universal sentences the quantifiers are customarily dropped.
BTW the above question is from A Tarski "Intro to logic..."