In this answer https://mathoverflow.net/a/335864/64128 to a question about whether it is possible in general to construct initial term models for infinitary equational theories, it is remarked that if all the arities of the operations are choice sets (and the operations themselves constitute a set), then the initial term model for such a theory can be constructed. So does this hold when the arities of the operations are all bounded by some regular cardinal?
2026-04-22 11:21:53.1776856913
Term models for bounded infinitary equational theories
36 Views Asked by Bumbble Comm https://math.techqa.club/user/bumbble-comm/detail At
1
There are 1 best solutions below
Related Questions in LOGIC
- Theorems in MK would imply theorems in ZFC
- What is (mathematically) minimal computer architecture to run any software
- What formula proved in MK or Godel Incompleteness theorem
- Determine the truth value and validity of the propositions given
- Is this a commonly known paradox?
- Help with Propositional Logic Proof
- Symbol for assignment of a truth-value?
- Find the truth value of... empty set?
- Do I need the axiom of choice to prove this statement?
- Prove that any truth function $f$ can be represented by a formula $φ$ in cnf by negating a formula in dnf
Related Questions in MODEL-THEORY
- What is the definition of 'constructible group'?
- Translate into first order logic: "$a, b, c$ are the lengths of the sides of a triangle"
- Existence of indiscernible set in model equivalent to another indiscernible set
- A ring embeds in a field iff every finitely generated sub-ring does it
- Graph with a vertex of infinite degree elementary equiv. with a graph with vertices of arbitrarily large finite degree
- What would be the function to make a formula false?
- Sufficient condition for isomorphism of $L$-structures when $L$ is relational
- Show that PA can prove the pigeon-hole principle
- Decidability and "truth value"
- Prove or disprove: $\exists x \forall y \,\,\varphi \models \forall y \exists x \,\ \varphi$
Trending Questions
- Induction on the number of equations
- How to convince a math teacher of this simple and obvious fact?
- Find $E[XY|Y+Z=1 ]$
- Refuting the Anti-Cantor Cranks
- What are imaginary numbers?
- Determine the adjoint of $\tilde Q(x)$ for $\tilde Q(x)u:=(Qu)(x)$ where $Q:U→L^2(Ω,ℝ^d$ is a Hilbert-Schmidt operator and $U$ is a Hilbert space
- Why does this innovative method of subtraction from a third grader always work?
- How do we know that the number $1$ is not equal to the number $-1$?
- What are the Implications of having VΩ as a model for a theory?
- Defining a Galois Field based on primitive element versus polynomial?
- Can't find the relationship between two columns of numbers. Please Help
- Is computer science a branch of mathematics?
- Is there a bijection of $\mathbb{R}^n$ with itself such that the forward map is connected but the inverse is not?
- Identification of a quadrilateral as a trapezoid, rectangle, or square
- Generator of inertia group in function field extension
Popular # Hahtags
second-order-logic
numerical-methods
puzzle
logic
probability
number-theory
winding-number
real-analysis
integration
calculus
complex-analysis
sequences-and-series
proof-writing
set-theory
functions
homotopy-theory
elementary-number-theory
ordinary-differential-equations
circles
derivatives
game-theory
definite-integrals
elementary-set-theory
limits
multivariable-calculus
geometry
algebraic-number-theory
proof-verification
partial-derivative
algebra-precalculus
Popular Questions
- What is the integral of 1/x?
- How many squares actually ARE in this picture? Is this a trick question with no right answer?
- Is a matrix multiplied with its transpose something special?
- What is the difference between independent and mutually exclusive events?
- Visually stunning math concepts which are easy to explain
- taylor series of $\ln(1+x)$?
- How to tell if a set of vectors spans a space?
- Calculus question taking derivative to find horizontal tangent line
- How to determine if a function is one-to-one?
- Determine if vectors are linearly independent
- What does it mean to have a determinant equal to zero?
- Is this Batman equation for real?
- How to find perpendicular vector to another vector?
- How to find mean and median from histogram
- How many sides does a circle have?
No. Indeed, this is answered by Andreas Blass's paper Words, free algebras, and coequalizers mentioned in the other answer to the question you linked. Namely, in section 9 he gives an example of an equational theory for which all operations have countable arity such that in a certain model of ZF, there does not exist any initial algebra. (Specifically, the theory has a constant $0$, a unary "successor" operation, and a $\omega$-ary "supremum" operation, together with axioms that say these behave reasonably. In a model where every limit ordinal has countable cofinality, you can reach all ordinals by iterating these operations, and this means that the initial algebra could not be a set.)