1. The problem statement, all variables and given/known data An extract from my notes reads that "every boolean law has a dual: any valid statement is also valid with:" . replaced with + + replaced with . 0 replaced with 1 and vice versa. 2. Relevant equations None 3. The attempt at a solution I have no clue what this means. Surely it doesn't mean that you can switch around the + and . in any boolean statement and it will still hold true? Can anyone explain, and what are the implications of it?