The Envelope Theorem is a concept in economics, particularly in the fields of optimization and comparative statics. It describes how the value of an optimal objective function changes with respect to changes in parameters of the model. The fundamental idea is that when evaluating the impact of a change in parameters on the optimal value of the objective function, we can typically simplify the analysis by looking at the optimal solution without needing to find the explicit form of the solution again.

The Lerner symmetry theorem, often associated with the economist Abba Lerner, relates to the behavior of taxes and subsidies in an economy. The theorem posits that under certain conditions, the effects of a tax and a subsidy on output can be considered symmetrical. In other words, if a good is taxed, removing the tax (or replacing it with a subsidy) leads to similar effects on the quantity produced and consumed, though the sign of the effect is reversed.

Roy's identity is a result in the theory of statistical inference, particularly in the context of Bayesian analysis. It relates the posterior distribution of a parameter of interest given observed data to the prior distribution and the likelihood of the data observed.

George Dantzig was an American mathematician and statistician, best known for his contributions to operations research and linear programming. He was born on November 8, 1914, and passed away on May 13, 2005. Dantzig developed the simplex algorithm, a method for solving linear programming problems, which has had a profound impact on various fields, including economics, engineering, and military logistics.

Ik Onkar is a fundamental concept in Sikhism, representing the oneness of God. The term is derived from the Gurmukhi script, where "Ik" means "one" and "Onkar" signifies the creative energy or essence of God. Together, "Ik Onkar" proclaims that there is only one supreme being, who is the source of all creation and is present in everything.

General disequilibrium refers to a situation in an economic model where supply and demand across multiple markets are not in balance simultaneously. This is in contrast to general equilibrium, where all markets clear (i.e., supply equals demand) at the same time, leading to a stable state for the entire economy. In a state of general disequilibrium, certain markets might experience excess supply (surpluses) while others may face excess demand (shortages).

The Fellows of the Econometric Society is an honorary group within the Econometric Society, an international organization founded in 1930 to promote the advancement of economic theory in its relation to statistics and mathematics. The Society recognizes distinguished contributions to the field of econometrics and economic theory by electing a select group of scholars as Fellows. Being named a Fellow is a mark of distinction that acknowledges individuals who have made significant contributions to the understanding of economic phenomena through mathematical and statistical methods.

Allan Gibbard is an American philosopher known for his work in ethics, political philosophy, and the philosophy of language. He is particularly noted for his contributions to the field of normative ethics, especially regarding the concept of meta-ethical expressivism, which asserts that ethical statements express emotional attitudes rather than factual claims. Gibbard is also recognized for his exploration of issues related to moral disagreement, moral reasoning, and the nature of normativity.

It seems there may be some confusion, as "Donald John Roberts" does not refer to a widely recognized public figure or concept as of my last knowledge update in October 2021. It is possible you meant to refer to "Donald John Trump," the 45th President of the United States, or "John Roberts," the Chief Justice of the United States Supreme Court.

Frederik Zeuthen may refer to a notable figure or concept related to economics, mathematics, or another field, but without more context, it is difficult to pinpoint precisely who or what you are referring to.

Harold Hotelling (1895–1973) was an American mathematician and statistician known for his work in various fields, including economics, statistics, and operations research. He is particularly well-known for several contributions: 1. **Hotelling's T-squared Distribution**: This is a multivariate statistical test that generalizes the Student's t-test to higher dimensions. It is used in hypothesis testing for comparing the means of multivariate data.

Olga Bondareva could refer to various individuals, as it is a relatively common name. However, without additional context, it's difficult to pinpoint a specific person or subject associated with that name.

Stephen Smale is an American mathematician known for his significant contributions to various fields, including topology, dynamical systems, and mathematical economics. Born on July 15, 1930, he has been recognized for his groundbreaking work, including the development of the theory of differentiable dynamical systems and his contributions to the study of manifolds. Smale is also famous for the "Smale horse-shoe map," which is a seminal example in the study of chaos in dynamical systems.

The risk-return ratio is a financial metric used to evaluate the relationship between the potential risk and the expected return of an investment. It helps investors assess whether the potential rewards of an investment justify the risks involved. A higher ratio generally indicates that the investment is providing a better return for the level of risk taken.

An "event segment" typically refers to a portion of an event or a specific category within an event, often used in various contexts such as marketing, data analytics, event management, and more. Here are some interpretations of what an event segment could mean: 1. **Marketing and Analytics**: In this context, an event segment could refer to a specific group of attendees or participants categorized based on their behaviors, demographics, interests, or interactions during an event.

Monte Carlo methods for option pricing are a set of computational algorithms that use random sampling to estimate the value of financial derivatives, particularly options. These methods are particularly useful for pricing complex derivatives that may not be easily solvable using traditional analytical methods. The Monte Carlo approach relies on the law of large numbers, which allows for convergence to the expected value through repeated sampling.

The LIBOR market model (LMM), also known as the Brace-Gatarek-Musiela (BGM) model, is a framework used in finance for modeling the evolution of interest rates in the context of the London Interbank Offered Rate (LIBOR). It is particularly useful for pricing and managing the risk of interest rate derivatives, such as interest rate swaps and caps/floors.

Morley rank is a concept from model theory, a branch of mathematical logic that deals with the study of structures and the formal languages used to describe them. Specifically, Morley rank helps to measure the complexity of definable sets in a given structure. The Morley rank of an element in a model is defined as follows: 1. **Elements and Types:** Consider a complete first-order theory and a model of that theory.

Property Specification Language (PSL) is a formal language used for specifying properties of hardware and software systems, particularly in the context of verification and model checking. It was developed as part of the IEEE standard 1850, and it provides a structured way to express properties such as safety, liveness, and temporal behaviors that a system should satisfy.

The Vienna Development Method (VDM) is a formal method for the specification, development, and verification of computer-based systems. It originated in the late 1970s and early 1980s in Vienna, Austria, particularly through the work of researchers like Jean-Raymond Abrial. VDM is particularly focused on providing a rigorous framework for the description of complex systems, allowing for formal reasoning about their properties.