Skip to main content

All Questions

Tagged with
4 votes
1 answer
204 views

Surjective homomorphism into a magma confers all the algebraic properties of the domain

Let $A$ be your favorite algebraic object (group, abelian group, rng, ring, commutative ring, field, module, vector space). Let $M$ be a magma. The image of a "homomorphism" $\phi : A \to M$ ...
jskattt797's user avatar
  • 1,751
3 votes
1 answer
224 views

Is there a category of partially defined binary operations?

A magma is a set $Y$ with a binary operation $m:Y \times Y \rightarrow Y.$ A partial magma is the same idea, but where the binary operation $m$ may not be defined on some pairs of elements of $Y.$ My ...
Richard Southwell's user avatar
5 votes
3 answers
753 views

What is difference between idempotent magma and unital magma?

I don't understand well in what way idempotent element is wired to identity element in a magma context. idempotent: $x \cdot x = x$ identity element: $1 \cdot x = x = x \cdot 1$ For example ...
Jack's user avatar
  • 65
4 votes
1 answer
387 views

Elegant approach to coproducts of monoids and magmas - does everything work without units?

From this answer by Martin Brandenburg I learned an elegant way of constructing and describing elements of coproducts of monoids. There he writes this construction shows the existence of colimits in ...
Arrow's user avatar
  • 14k
2 votes
1 answer
127 views

Concretely describing the arrow $A\amalg B\to A\times B$ for nonlinear algebraic theories

I'm reading about unital categories to get a better understanding of nonlinear algebraic categories like groups, monoids, semigroups, magmas etc. A unital category is a pointed finitely complete ...
Arrow's user avatar
  • 14k
2 votes
1 answer
1k views

Associativity in category theory [closed]

In Category Theory, the composition of morphisms must be associative. What would happen if we give up this associative law? For example Lie algebras are vector spaces with non-associative binary ...
bill's user avatar
  • 69
4 votes
2 answers
165 views

Are epimorphisms in the category of magmas surjective?

The question says it all, but let me recall the definitions. A magma $(X, \cdot)$ is a set $X$ with a binary operation $\cdot \colon X \times X \to X$ (without any further assumptions like ...
Jochen's user avatar
  • 12.3k
4 votes
1 answer
207 views

How to describe free magmas in more structuralist terms?

Given a generating set $G$ (assume for simplicitly it consists entirely of urelements), the free magma on $G$ can be described concretely as follows. Its underlying set is the least $U \supseteq G$ ...
goblin GONE's user avatar
  • 68.1k