# meetExists -- determines if the meet exists for two elements of a poset

## Synopsis

• Usage:
m = meetExists(P, a, b)
• Inputs:
• P, an instance of the type Poset,
• a, , an element of the poset
• b, , an element of the poset
• Outputs:
• m, , whether the meet exists for $a$ and $b$ in $P$

## Description

The meet of $a$ and $b$ in $P$, if it exists, is the unique greatest element less than both $a$ and $b$.

 i1 : P = poset {{a,b}, {a,c}, {b,d}, {c,d}, {e,d}}; i2 : meetExists(P, b, c) o2 = true i3 : meetExists(P, b, e) o3 = false i4 : Q = poset {{a,b}, {a,c}, {d,b}, {d,c}, {b,e}, {c,e}}; i5 : meetExists(Q, b, c) o5 = false