Axiom:Boolean Algebra/Axioms/Formulation 2
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Axiom
A Boolean algebra is an algebraic system $\struct {S, \vee, \wedge, \neg}$, where $\vee$ and $\wedge$ are binary, and $\neg$ is a unary operation.
Furthermore, these operations are required to satisfy the following axioms:
\((\text {BA}_2 0)\) | $:$ | Closure: | \(\ds \forall a, b \in S:\) | \(\ds a \vee b \in S \) | |||||
\(\ds a \wedge b \in S \) | |||||||||
\(\ds \neg a \in S \) | |||||||||
\((\text {BA}_2 1)\) | $:$ | Commutativity: | \(\ds \forall a, b \in S:\) | \(\ds a \vee b = b \vee a \) | |||||
\(\ds a \wedge b = b \wedge a \) | |||||||||
\((\text {BA}_2 2)\) | $:$ | Associativity: | \(\ds \forall a, b, c \in S:\) | \(\ds a \vee \paren {b \vee c} = \paren {a \vee b} \vee c \) | |||||
\(\ds a \wedge \paren {b \wedge c} = \paren {a \wedge b} \wedge c \) | |||||||||
\((\text {BA}_2 3)\) | $:$ | Absorption Laws: | \(\ds \forall a, b \in S:\) | \(\ds \paren {a \wedge b} \vee b = b \) | |||||
\(\ds \paren {a \vee b} \wedge b = b \) | |||||||||
\((\text {BA}_2 4)\) | $:$ | Distributivity: | \(\ds \forall a, b, c \in S:\) | \(\ds a \wedge \paren {b \vee c} = \paren {a \wedge b} \vee \paren {a \wedge c} \) | |||||
\(\ds a \vee \paren {b \wedge c} = \paren {a \vee b} \wedge \paren {a \vee c} \) | |||||||||
\((\text {BA}_2 5)\) | $:$ | Identity Elements: | \(\ds \forall a, b \in S:\) | \(\ds \paren {a \wedge \neg a} \vee b = b \) | |||||
\(\ds \paren {a \vee \neg a} \wedge b = b \) |
Also see
Sources
- 1993: Keith Devlin: The Joy of Sets: Fundamentals of Contemporary Set Theory (2nd ed.) ... (previous) ... (next): $\S 1$: Naive Set Theory: $\S 1.8$: Problems: $1$
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): Boolean algebra
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): Boolean algebra