Questions tagged [utility]

Utility, or usefulness, is the (perceived) ability of something to satisfy needs or wants.

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9
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1answer
15k views

Finding demand function given a utility min(x,y) function

I am confused about a particular point regarding finding a demand function. All the problems in this practice set I am doing have involved applying the method of Lagrangian multipliers. But I am ...
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2answers
19k views

Lexicographic preference relation cannot be represented by a utility function

I am stuck on the following exercise, related to preference relations and von-Neumann-Morgenstern utility function. A farmer wants to dig a well in a square field $[0,1000]\times[0,1000]$. The ...
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5answers
848 views

Are there Utility Monsters in Economics?

Economics, especially in the modern school is broadly influenced by the utilitarian concept of utility. More so since the labor theory of value has been broadly replaced by the theory of marginal ...
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12answers
14k views

If I gain, then someone else loses. Correct?

On a very small scale, it's certainly true that if I gain, somebody else might lose. If I take away my brother's chocolate, then he will lose it, and will most probably not get anything comparable. ...
14
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2answers
12k views

The relationship between the expenditure function and many others!

I dont understand the relationships between Hicksian demand, walrasian demand (marshallian), the expenditure function and the indirect utility function (including the value function V(b)). I have ...
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4answers
15k views

What is an example of a utility function where one good is inferior?

Say the consumer has a standard convex, monotonic preference over Apples and Bananas. (Update: I'd like the preference to be as 'standard' as possible. So ideally we have diminishing MRS everywhere ...
6
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2answers
3k views

Local Non-Satiation Proof

I have been having trouble with how to go forward with a proof for about three days now. I know the basic structure of the proof, but can't seem to construct it. Basically, I am trying to do a proof ...
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3answers
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Question about the Ellsberg Paradox in Expected Utility Theory

The von Neumann-Morgenstern theorem states that, assuming a person's preferences under risk satisfy certain rationality axioms, then there exists a utility function u, the von Neumann utility function,...
9
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2answers
1k views

When can one safely talk about decreasing marginal utility?

One thing I hear a lot is talk of decreasing marginal utility—the idea being that additional units of a good become progressively less attractive the more units of that good one has already. However, ...
7
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2answers
3k views

Which utility function yields a constant price elasticity of demand function?

How do I know which utility function I can use to find an isoelastic demand function, e.g., $x(p)=Ap^a$? And similarly, which cost function can I use to find an isoelastic supply function? Does it ...
6
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1answer
2k views

Homothetic preferences and utility functions

I know that if you have homothetic preferences and a utility function that represents it, then this utility function must present constant Marginal Rate of Substitution (MRS). My question is whether ...
5
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3answers
562 views

Preferences where wealth effect dominates

King-Plosser-Rebelo preferences satisfy balanced growth requirements, we have that income and substitution effects of labor cancel. Labor does not respond to a change in the wage level. Greenwood-...
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1answer
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Linear Expenditure System of Demands, Derivation Help

This problem I am working on comes out of--surprise--the Mas-Colell book for graduate micro (3.D.6). I think I have correctly used the FOC of the Lagrangian of the utility maximization problem to ...
3
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1answer
7k views

Monotone transformation of utility

We have learned that any "strictly positive monotonous transformation" of utility functions is okay, as long as they preserve the ranking of choices implied by the underlying preferences. Consider $U(...
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1answer
460 views

If a utility function is quasi-concave, can we say that the IC curve associated with it is convex?

Let's say we have an utility function, $ U(x,y) = \sqrt{x \cdot y} $. The indifference curve associated with this is convex, while the function itself is quasi concave (because it satisfies $ f_{xx} ...
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1answer
70 views

Would a very cheap renewable energy source be harmful economically?

This question is not on whether these devices work or not but so much as if they did work. What if electricity can be made so cheap that everyone could afford it ti the point there was no demand for ...
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5answers
14k views

Help understanding Lagrangian multipliers?

I am trying to understand Lagrangian multipliers and using an example problem I found online. Problem Set Up: Consider a consumer with utility function $u(x,y) = x^{\alpha} y^{1-\alpha}$, where $\...
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3answers
1k views

Does risk aversion cause diminishing marginal utility, or vice versa?

Let $A$ be the set of possible states of the world, or possible preferences a person could have. Let $G(A)$ be the set of "gambles" or "lotteries", i.e. the set of probability distributions over $A$. ...
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3answers
194 views

Current knowledge about the empirics of consumer theory

I would like to get up to speed on the current state of empirical work done to test the assumptions and predictions of consumer theory (think Chapters 1, 2, 3, and 6 of Mas-Colell et al.). Can anyone ...
8
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2answers
502 views

Doesn't the concept of marginal utility speak to a cardinal utility function?

When we differentiate the utility function with respect to some input $x_i$, we get a number that tells us how "fast" the utility function is changing at some point with respect to $x_i$. Doesn't that ...
6
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2answers
819 views

Calculate the elasticity of substitution of Epstein-Zin preferences

$$ \newcommand{\E}{\mathbb{E}} $$ Let a consumption sequence be given $C=(C_0, C_1,...)$ and let $C_t^+ = (C_t, C_{t+1}, ...)$. Now, suppose I have Epstein-Zin preferences, \begin{align*} U_t(C_t^+) &...
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2answers
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Why does local non satiation imply the constraint is binding?

Local non satiation says that for any $x \in X$ and $\epsilon > 0$, there exists $y \in X$ such that $d(x,y) < \epsilon$ and $U(x) < U(y)$. I don't understand why this implies that $px^* = m$...
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3answers
12k views

How to show that a homothetic utility function has demand functions which are linear in income

A homothetic utility function is one which is a monotonic transformation of a homogeneous utility function. I am asked to show that if a utility function is homothetic then the associated demand ...
7
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4answers
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Existence of utility representation of a rational but discontinuous preference

This is related to Do discontinuous preferences imply no continuous utility function? I think the title of the above-linked question is phrased in such a way that obscures a subtly different but more ...
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2answers
9k views

How to derive utility possibility frontier?

I'm trying to derive the utility possibility frontier of a economy whose consumption contract curve is $$y_A = \frac {y} {x} x_A$$ and $$y_B = \frac {y} {x} x_B$$where $x_A + x_B = x$ and $y_A + y_B= ...
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2answers
13k views

How can I tell if 2 different utility functions represent the same preferences?

I need to verify that $u(x,y)=x^{1/3}y^{1/3}$ represents the same preferences as $v(x,y)=x^3y^3$. Obviously these are completely different functions with different derivatives, so what am I comparing? ...
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1answer
297 views

Question on consumer theory

The story of my question is I have multiple question. (1) when John doesn’t work in the underground economy at all , t=0, how can I find the optimal value of $l$ and consumption bundle and his ...
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3answers
15k views

Can A Utility Function Take On Negative Values?

Can someone provide a rigorous definition of a utility function? I had thought that a utility function only needs to the preserve the order of preferences. Thus a utility function can take on negative ...
6
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1answer
235 views

Generalized KPR: Frisch Elasticity

Consider the following version of KPR preferences (with $l$ being leisure): $$ U(c,l) = \left(\left(c\right)^\gamma l^\omega\right)^{1-\sigma}$$ I'm after the Frisch elasticity: $$ \frac{\partial(1-...
5
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2answers
116 views

Utility function for introductory microeconomics

What are the utility functions standardly used in introductory microeconomics courses. My own list would include Perfect substitutes: $U(x,y) = ax+by$ Perfect complements: $U(x,y) = \min(ax,by)$ Cobb ...
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2answers
2k views

Do discontinuous preferences imply no continuous utility function?

I am trying to think of a preference relation that can be represented by a utility function but such that there does not exist a continuous utility function. I know that you can represent continuous ...
4
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2answers
319 views

Ruling out boundary solutions in Utility Maximization

Solving the basic Utility Maximization Problem, i.e. \begin{align} max_{x\geq 0} u(x) \\ s.t. \,\,\, p^Tx\leq w \end{align} we get the Kuhn-Tucker first order condition \begin{gather} \frac{\...
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1answer
549 views

What is the assumption behind “indifference curve does not cross”?

If only weak-ordering and continuity is assumed, "ICs" can definitely intersect. If we assume Monotonicity or convexity in addition to weak-ordering, then we can get "no cross of IC". But those two ...
3
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3answers
351 views

Consumer preferences

I want to know under what preferences relation will I not want to consume all of my budget. Because if my preferences are strictly monotonic, strictly convex or convex, even LNS or continuous. I would ...
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1answer
88 views

Find Pareto optimal allocations and the core for the following economies

Find Pareto optimal allocations and the core for the following economies. There are two consumers and two goods. Utility functions are $u_1(x_1,y_1)= 10x_1-(y_1-2)^2$ and $u_2(x_2,y_2) = 10y_2 − (x_2 −...
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1answer
542 views

Question about budget constraint and utility maximization [closed]

I have also following budget set $$B=\{x=(x_1,x_2)\in R^2_+ \mid 2\sqrt{x_1}+x_2\le y\}$$ where y is income. Assume that there are two stories. The agent can shop in both of them. The first store ...
5
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2answers
1k views

Why do so many models assume homothetic preferences?

...when Engels Law, backed by a good amount empirical evidence, demonstrates that overall consumer preferences are not homothetic. See for example, Jorgenson (1997)
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2answers
14k views

Cobb-Douglas and Logarithm Utility Functions

Suppose I have a consumer with a utility function $U(x,y) = x^\alpha y ^{1-\alpha} $ where $a \in (0,1)$. Suppose this consumer has wealth $w$ and the prices for $x$ and $y$ are $p_x$ and $p_y$ ...
4
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1answer
451 views

A term for utility functions based on the max operator

What is a standard term for utility functions of the type: $$ u(x_1,\dots,x_m) = \max(\frac{x_1}{w_1},\dots,\frac{x_m}{w_m}) $$ where $x_i$ is the amount of commodity type $i$, and $w_i$ is a ...
4
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2answers
119 views

Is there any evidence for consumer utility-maximising behaviour, at individual or market level?

Even though utility maximisation is ubiquitous in economic textbooks to model consumer behaviour, its usefulness is rarely demonstrated by evidence. Is there any evidence that some consumers do ...
4
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1answer
114 views

Are the goods in additively separable utility functions normal goods?

Inspired by this answer. To make it a bit more precise, by normal good I mean demand is (not necessarily strictly) increasing in income, and by additively separable utility function I mean that a ...
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2answers
1k views

Is the Cobb-Douglas Utility Function Locally Non-Satiated at (0,0)?

My understanding of local non-satiation is that increasing your allocation of one good by a marginal amount increases utility. Suppose your utility takes the following form: $$U(x,y)=x^\alpha y^\beta$$...
3
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0answers
128 views

Fixes of quadratic utility when probability of decreasing utility is large

In finance and specifically portfolio theory, a popular utility function is quadratic utility $$ u(x)=x-\frac{\lambda}{2}(x-\mu_x)^2 $$ where $x$ is wealth and $\lambda$ is the parameter of risk ...
3
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1answer
2k views

Positive Monotonic Transformations and Nested Functions

Suppose there is an economic agent with the utility function $u(x,y)$. A second agent has the utility function $h(g(f(u(x,y))))$. Am I correct in thinking that if $f'(x)>0$, $g'(x)>0$, and $h'(...
2
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1answer
525 views

Utility theory and portfolio optimization: utility of what exactly?

In finance, a common problem is selection of an optimal portfolio given some constraints (e.g. budget constraint and perhaps nonnegative allocation constraint). One can define the optimization problem ...
2
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1answer
72 views

What was “Pareto's proof of the immeasurability of utility”?

Wong (1978, 2002, Foundations of Paul Samuelson's Revealed Preference Theory), repeatedly refers to "Pareto’s proof of the immeasurability of utility". What was this proof?
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2answers
346 views

Continuation value versus utility in asset pricing

Is there a difference between continuation value ($V_t$) and utility ($U_t$) except for a possible scaling / difference in units? My question refers to the consumption-based asset pricing literature. ...
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1answer
328 views

What is the concept of ordinal utility?

I have read in many books that since utility cannot be measured - so ordinal concept or comparison concept is used. If that is so, how can one define a mathematical function for utility which gives a ...
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1answer
332 views

What would the indifference curve of min{√x,y} looks like?

The locus of kinks would follow x=y^2 but what would the arms look like?
0
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1answer
42 views

Why might a monotone increasing but nonlinear transformation of a utility function not represent the same preferences?

According to a textbook, a monotone increasing but nonlinear transformation of a utility function might not represent the same preferences. Why is it so? An example of such preference would be ...