
What is the difference between disjoint union and union?
The notation A ⊔ B A ⊔ B (and phrase "disjoint union") has (at least) two different meanings. The first is the meaning you suggest: a union that happens to be disjoint.
Pairwise disjoint or disjoint? - Mathematics Stack Exchange
Jun 24, 2017 · The term disjoint refers to a collection of subsets, it means that its subsets are disjoint. The term pairwise disjoint refers to a familly of collections of subsets. It not only means that any two …
What does pairwise disjoint mean? - Mathematics Stack Exchange
Mar 9, 2019 · Typically, pairwise disjoint means that no two sets in the collection have a member in common. The answer to your first question is no, in fact each pair of distinct subsets has a common …
Why do we say ‘pairwise disjoint’, rather than ‘disjoint’?
Mar 8, 2019 · A "disjoint union" is a union of pairwise disjoint sets; one does not say "pairwise disjoint union". To corroborate my point of view, here is a citation from Halmos: Pairs of sets with an empty …
general topology - Confusion on pairwise disjoint and disjoint ...
Feb 4, 2021 · The term disjoint may serve as a shortcut either for pairwise disjoint or collectionwise disjoint depending on the used convention (but obviously not both at the same time).
What's the difference between MUTUALLY EXCLUSIVE and PAIRWISE …
Mar 7, 2018 · With that definition, disjoint sets are necessarily mutually exclusive, but mutually exclusive events aren't necessarily disjoint. Consider points in the square with each coordinate uniformly …
elementary set theory - Does distinct sets mean disjoint sets ...
Nov 13, 2020 · I am confused here that whether distint and disjoint sets mean the same? I have to find the intersection of two sets. It could be empty set if these two sets are disjoint. And it could be any …
What is mutually disjoint sets - Mathematics Stack Exchange
Apr 22, 2015 · What is mutually disjoint sets? I know it has something to do with subsets but I don't know for sure.
Any open subset of $\\Bbb R$ is a countable union of disjoint open ...
Clearly, collection of open intervals is a base for the standard topology. Hence any open set in $\mathbb {R}$ can be written as countable union of open intervals. If any two of exploited open intervals …
Definition of Disjoint Union Spaces - Mathematics Stack Exchange
Sep 24, 2018 · The following is the definition of disjoint union spaces in John Lee's "Introduction to Topological Manifolds": Let (Xα)α ∈ A be an indexed family of nonempty topological spaces.