"Perfect. Except that a valid transaction is also not spent by definition so that's redundant." -- @Richy_T
I see what you mean, but I think it's helpful to think of a transaction being valid independently from a transaction being already spent. For example, you could broadcast two valid transactions at the same time, but once one is confirmed, the other one cannot be double spent.
I see what you mean, but I think it's helpful to think of a transaction being valid independently from a transaction being already spent. For example, you could broadcast two valid transactions at the same time, but once one is confirmed, the other one cannot be double spent.