FYI, you don't call the symbol for the empty set "phi". Phi is a greek letter that looks a little similar to the symbol for the empty set, but mathematicians are not using the greek letter phi in this case, it is just it's own symbol that denotes the empty set.
@@AkamiChannel Perhaps not super-surprising? It's possible to be knowledgable in a field without having heard the terms of the field spoken in _english_.
i figured it out, the elements that can be GLB in (f,g) are e and b. Since you cannnot determine whether e is greater than b or b is greater than e due to the lack of relationship between e and b, there is no GLB. The same logic applies to determine the GLB and LUB of other pair of elements.
GLB(f,g) for all pair isn't defined, thus the set is empty. since the two preceding lower bounds are incomparable, we can't define greatest lower bound.
Lower bound of (f,g) - abce Let's check for GLB : a - All elements of LB related to a ? No [Using Hasse Diagram] b - All elements of LB related to b ? No [Using Hasse Diagram] c - All elements of LB related to c ? Obviously No [Using Hasse Diagram] e - All elements of LB related to e ? Obviously No [Using Hasse Diagram] So, GLB = Phi
