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

Synopsis

• Usage:

  j = joinExists(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:
  • j, a Boolean value, whether the join exists for $a$ and $b$ in $P$

Description

i1 : P = poset {{a,b}, {a,c}, {a,d}, {c,e}, {d,e}};

i2 : joinExists(P, b, c)

o2 = false

i3 : joinExists(P, c, d)

o3 = true

i4 : Q = poset {{a,b}, {a,c}, {b,d}, {c,d}, {b,e}, {c,e}};

i5 : joinExists(P, b, c)

o5 = false

See also

• meetExists -- determines if the meet 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