Exercise · ZW-LATTICE-OR-ORDER-THEORY-008 · ★★☆ Intermediate

In the poset \(L=\{\hat{0},a,b,c,\hat{1}\}\) with \(\hat{0}<a,b<c<\hat{1}\), what is \(a \wedge b\)?

Choose one option.

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  • D. \(\hat{0}\)

Explanation

The only common lower bound of \(a\) and \(b\) is \(\hat{0}\), so it is their infimum.

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Review the concept: Lattice or order theory

A lattice is a partially ordered set (L, ≤) in which every pair of elements x and y has a supremum (x ∨ y) and an infimum (x ∧ y).

\[x \vee y = \sup\{x,y\}, \quad x \wedge y = \inf\{x,y\}\]

More practice problems: lattice or order theory

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