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

- Usage:
    `m = meetExists(P, a, b)`
- Inputs:
  - P, an instance of the type Poset,
  - a, a thing, an element of the poset
  - b, a thing, an element of the poset
- Outputs:
  - m, a Boolean value, 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

## See also

- joinExists -- determines if the join exists for two elements of a poset
- posetJoin -- determines the join for two elements of a poset
- posetMeet -- determines the meet for two elements of a poset

## Ways to use meetExists:

- `meetExists(Poset,Thing,Thing)`

## For the programmer

The object meetExists is a method function.

The source of this document is in /build/macaulay2-88fgJW/macaulay2-1.25.11+ds/M2/Macaulay2/packages/Posets.m2:4432:0.