What ⊍ means
Usually a disjoint union; officially, multiset multiplication.
The cup means union: everything in either set. Many textbooks, especially in German-speaking countries, put a dot on the cup to say the joined sets have nothing in common, so A B is a disjoint union. Typed text often uses ⊍ for that dotted cup, so in a proof or lecture note this is the likeliest reading.
Its Unicode name comes from multisets, collections where an item can appear several times, such as {a, a, b}. Its neighbour (cup with a plus) adds the counts of each item; ⊍, by its name, is the multiplying counterpart. That use is rare, so check how the author defines it.
Pure mathematical notation for formal writing; it has no place or meaning in casual chat.
Don't swap ⊍ and : dot and plus mark different operations.
Part of collections
Don't confuse it with
3
Related characters
1
Questions people ask
2Is ⊍ the same as disjoint union?
Often, yes. Many authors use the dotted cup for a disjoint union; others write or . The text's own definition settles it.
Why doesn't the dot show?
Your font lacks a good glyph for U228D. A math font such as Cambria Math or STIX shows it clearly.
More like this
9
How to type or find ⊍
- Also called
- cup with dot · union with dot · dotted union
- Search it as
- disjoint union · multiset · multiset product · ⊎
- Shows up in
- Anything that takes text · its shape is whatever your font draws
⊍\228DCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.