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21 August 2026
- 03:5003:50, 21 August 2026 Quick ratio (hist | edit) [5,291 bytes] WikiSysopIG (talk | contribs) (Created page with "The '''Quick ratio''', also known as the '''acid-test ratio''', is a liquidity ratio that measures an entity's ability to meet its short-term liabilities using assets that can be converted into cash relatively quickly. A simplified formula is: <math> \text{Quick Ratio} = \frac{\text{Cash and Cash Equivalents} + \text{Marketable Securities} + \text{Accounts Receivable}} {\text{Current Liabilities}} </math> An equivalent formulation is: <math> \...")
- 03:4903:49, 21 August 2026 Liquidity Coverage Ratio (hist | edit) [5,973 bytes] WikiSysopIG (talk | contribs) (Created page with "The '''Liquidity Coverage Ratio''' ('''LCR''') is a liquidity risk measure designed to assess whether a bank holds sufficient high-quality liquid assets (HQLA) to withstand a specified period of stressed net cash outflows. The ratio is generally expressed as: <math> \text{LCR} = \frac{\text{Stock of High-Quality Liquid Assets}} {\text{Total Net Cash Outflows over the Stress Period}} \times 100 </math> Under the Basel III fram...")
- 03:4903:49, 21 August 2026 Solvency risk (hist | edit) [11,222 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Solvency risk''' is the risk that an individual, company, financial institution, or other entity will be unable to meet its long-term financial obligations because the value of its assets is insufficient to cover its liabilities or because its financial position has deteriorated to the point where continued operation or access to financing becomes unsustainable. A simplified representation is: <math> \text{Solvency Risk} \rightarrow \text{Insufficient Assets or...")
- 03:4803:48, 21 August 2026 Liquidity risk (hist | edit) [10,331 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Liquidity risk''' is the risk that an individual, company, financial institution, or market participant cannot meet financial obligations when they become due without incurring unacceptable losses. Liquidity risk can arise when an entity does not have sufficient cash or readily available funding, or when an asset cannot be sold or financed quickly enough at or near its prevailing market value. A simplified representation is: <math> \text{Liquidity Risk} \righta...")
- 03:4703:47, 21 August 2026 Leverage (finance) (hist | edit) [8,499 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Financial leverage''' is the use of borrowed funds, debt, or other financial mechanisms to increase an investor's or company's exposure to an asset or investment relative to the amount of capital directly contributed. Leverage can magnify both gains and losses. A simplified leverage relationship is: <math> \text{Leverage} = \frac{\text{Total Asset Exposure}} {\text{Investor Equity}} </math> where: * <math>\text{Total Asset Exposure}</math>...")
- 03:4403:44, 21 August 2026 Zero trust (hist | edit) [10,611 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Zero trust''' is a cybersecurity security model based on the principle that access to information systems and resources should not be implicitly trusted solely because a user, device, application, or network connection is located within a trusted network boundary. Instead, access is continuously evaluated using factors such as identity, device security, application context, resource sensitivity, and other relevant signals. A simplified principle is: <math> \tex...")
20 August 2026
- 13:0813:08, 20 August 2026 Technological singularity (hist | edit) [8,902 bytes] WikiSysopIG (talk | contribs) (Created page with "The '''technological singularity''', also known as the '''singularity''', is a hypothetical future point at which technological development becomes so rapid and transformative that the resulting changes become difficult or impossible for humans to predict or control. The concept is particularly associated with the possibility that artificial intelligence (AI) systems could reach or exceed human-level capabilities and subsequently contribute t...")
- 13:0613:06, 20 August 2026 Margin call (hist | edit) [7,276 bytes] WikiSysopIG (talk | contribs) (Created page with "A '''Margin call''' is a demand from a broker or other financial intermediary requiring an investor to provide additional funds or eligible collateral when the value of a margin account falls below the required maintenance margin. Margin calls can arise when the market value of securities purchased with borrowed funds declines, when the value of collateral falls, or when applicable margin requirements increase. ==Margin account== When...")
- 13:0313:03, 20 August 2026 Heteroskedasticity-consistent standard errors (hist | edit) [7,791 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Heteroskedasticity-consistent standard errors''' ('''HC standard errors''') are standard-error estimators used in regression analysis to provide inference that is robust to heteroskedasticity of the regression errors. In an ordinary least squares (OLS) regression: <math> \mathbf{y} = \mathbf{X}\boldsymbol{\beta} + \boldsymbol{\epsilon} </math> the conventional OLS covariance matrix assume...")
- 13:0213:02, 20 August 2026 Heteroskedasticity (hist | edit) [6,727 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Heteroskedasticity''' is a condition in regression analysis in which the variance of the error term is not constant across observations. In a regression model: <math> Y_i = \beta_0 + \beta_1X_{1,i} + \cdots + \beta_kX_{k,i} + \epsilon_i </math> homoskedasticity requires the conditional variance of the error term to be constant: <math> \operatorname{Var}(\epsilon_i\mid\mathbf{X}) = \sigma^2 </math> Under heteroskedasticity, the conditio...")
- 13:0013:00, 20 August 2026 Alpha (finance) (hist | edit) [8,496 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Alpha''' is a measure of an investment's performance relative to the return that would be expected from a specified benchmark, market model, or set of risk factors. In a regression-based framework, alpha is commonly represented by the intercept of a return regression. For a simple market model: <math> R_i = \alpha_i + \beta_iR_m + \epsilon_i </math> where: * <math>R_i</math> = return of asset or portfolio <math>i</math>; * <math>\alpha_i</math...")
- 13:0013:00, 20 August 2026 Multiple linear regression (hist | edit) [10,878 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Multiple linear regression''' is a statistical method used to model the relationship between a dependent variable and two or more explanatory variables. It extends simple linear regression by allowing multiple explanatory variables to be included in the same model. A general multiple linear regression model is: <math> Y_i = \beta_0 + \beta_1X_{1,i} + \beta_2X_{2,i} + \cdots + \beta_kX_{k,i} + \epsilon_i </math> where: * <math>Y_i</math> =...")
- 12:5912:59, 20 August 2026 Regression analysis (hist | edit) [11,295 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Regression analysis''' is a set of statistical methods used to examine the relationship between a dependent variable and one or more explanatory variables. It is used to estimate relationships, quantify associations, test hypotheses, and generate predictions. In its simplest form, regression analysis models a dependent variable <math>Y</math> as a function of an explanatory variable <math>X</math>: <math> Y_i = \beta_0 + \beta_1X_i + \epsilon_i </math> where:...")
- 12:5812:58, 20 August 2026 Ordinary least squares (hist | edit) [8,862 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Ordinary least squares''' ('''OLS''') is a method for estimating the parameters of a linear regression model by minimizing the sum of the squared differences between observed and fitted values. For a simple linear regression model: <math> Y_i = \beta_0 + \beta_1X_i + \epsilon_i </math> the fitted value is: <math> \hat{Y}_i = \hat{\beta}_0 + \hat{\beta}_1X_i </math> and the residual is: <math> e_i = Y_i-\hat{Y}_i </math> The OLS estimat...") Tag: Visual edit: Switched
- 12:5712:57, 20 August 2026 Coefficient of determination (hist | edit) [6,898 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Coefficient of determination''' is a statistical measure that indicates the proportion of the variation in a dependent variable that is explained by a statistical model. It is commonly denoted by <math>R^2</math> and is widely used in linear regression. For a regression model with an intercept, the coefficient of determination can be expressed as: <math> R^2 = 1- \frac{\mathrm{SS}_{\mathrm{res}}} {\mathrm{SS}_{\mathrm{tot}}} </math> where:...")
- 12:5712:57, 20 August 2026 Linear regression (hist | edit) [8,207 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Linear regression''' is a statistical method used to model the relationship between a dependent variable and one or more explanatory variables by estimating a linear function. In the simplest case, linear regression relates one dependent variable <math>Y</math> to one explanatory variable <math>X</math>. A simple linear regression model is: <math> Y_i = \beta_0 + \beta_1X_i + \epsilon_i </math> where: * <math>Y_i</math> = observed value of the dependent varia...")
- 12:5012:50, 20 August 2026 Variance (hist | edit) [7,137 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Variance''' is a statistical measure of the dispersion of observations around their mean. It measures the average squared deviation from the mean. In finance, variance is commonly used to measure the variability of investment returns and is an important component of volatility, portfolio risk, and portfolio theory. ::contentReference[oaicite:0]{index=0} ==Population variance== For a population of <math>N</...")
- 12:4912:49, 20 August 2026 Pearson correlation coefficient (hist | edit) [6,467 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Pearson correlation coefficient''' is a statistical measure of the strength and direction of the linear relationship between two variables. It is commonly used in statistics, economics, finance, and other quantitative fields. The Pearson correlation coefficient is commonly denoted by <math>r</math> for a sample and <math>\rho</math> for a population. Its value ranges from −1 to +1: <math> -1\leq r\leq1 </math> A value close to +1 indicates a strong positive...")
- 12:4812:48, 20 August 2026 Covariance (hist | edit) [7,243 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Covariance''' is a statistical measure of the extent to which two variables tend to vary together. In finance, covariance is commonly used to measure the joint movement of the returns of two assets and is an important component of portfolio risk calculations. A positive covariance indicates that two variables tend to move in the same direction, while a negative covariance indicates that they tend to move in opposite directions. ==Populati...")
- 12:4712:47, 20 August 2026 Correlation (hist | edit) [6,924 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Correlation''' is a statistical measure of the degree to which two variables move together. In finance, correlation is commonly used to measure the strength and direction of the relationship between the returns of two assets. The Pearson correlation coefficient is commonly used to measure linear correlation. A correlation coefficient ranges from −1 to +1: <math> -1\leq\rho_{XY}\leq1 </math> where: * <math>\rho_{XY}=+1</math> indicates perfect positive l...")
- 12:4612:46, 20 August 2026 Standard deviation (hist | edit) [6,055 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Standard deviation''' is a statistical measure of the dispersion of observations or returns around their mean. In finance, it is commonly used to measure the variability of an asset's returns and is often used as a measure of total risk or volatility. A higher standard deviation indicates that observations are more widely dispersed around the mean, while a lower standard deviation indicates that observations are more closely concentrated around the mean. ==Popul...")
- 12:4512:45, 20 August 2026 Volatility (finance) (hist | edit) [10,021 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Volatility''' is a statistical measure of the degree to which the price or return of a financial asset fluctuates over time. It is commonly used as a measure of market risk and uncertainty. Higher volatility indicates larger or more frequent fluctuations in an asset's price or returns, while lower volatility indicates relatively smaller fluctuations. ==Concept== Volatility is commonly measured using the Standard deviation|standard deviati...")
- 12:4512:45, 20 August 2026 Put option (hist | edit) [6,446 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Put option''' is a type of option that gives the holder the right, but not the obligation, to sell an underlying asset at a predetermined price on or before a specified date, depending on the option's exercise terms. The predetermined price is known as the '''strike price''' or '''exercise price'''. The buyer of a put option generally pays a '''premium''' to the option seller for this right. ==Concept== A simplified put option can be repres...")
- 12:4412:44, 20 August 2026 Call option (hist | edit) [7,138 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Call option''' is a type of option that gives the holder the right, but not the obligation, to buy an underlying asset at a predetermined price on or before a specified date, depending on the option's exercise terms. The predetermined price is known as the '''strike price''' or '''exercise price'''. The buyer of a call option generally pays a '''premium''' to the option seller for this right. ==Concept== A simplified call option can be repr...")
- 12:3712:37, 20 August 2026 Payment tokenization (hist | edit) [9,295 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Payment tokenization''' is a data-security process in which sensitive payment information, such as a primary account number (PAN), is replaced with a non-sensitive substitute known as a '''payment token'''. The token can be used in payment transactions without exposing the underlying card information to merchants or other parties that do not need access to it. :contentReference[oaicite:0]{index=0} Payment tokenization is used to reduce...")
- 12:3512:35, 20 August 2026 Short selling (hist | edit) [10,430 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Short selling''' is a trading strategy in which an investor sells a security that they do not currently own, typically by borrowing the security, with the expectation that its market price will decline. The investor later seeks to purchase the security at a lower price and return it to the lender. Short selling is commonly used for speculation, hedging, and portfolio risk management. ==Concept== A simplified short-selling t...")
- 12:3412:34, 20 August 2026 Speculation (finance) (hist | edit) [10,661 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Financial speculation''' is the practice of taking a financial position with the expectation of profiting from anticipated changes in the price, value, or other characteristics of an asset or financial instrument. Speculators generally accept market risk in pursuit of potential returns. Unlike hedging, which primarily seeks to reduce or offset an existing exposure, speculation generally involves deliberately assuming or increasin...")
- 12:2912:29, 20 August 2026 Forward contract (hist | edit) [13,031 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Forward contract''' is a derivative contract in which two parties agree to buy or sell an underlying asset, financial instrument, or other reference at a predetermined price on a specified future date. The predetermined price is commonly called the '''forward price'''. Unlike an option, a forward contract generally creates an obligation for both parties to complete the transaction according to the contractual terms....")
- 12:2812:28, 20 August 2026 Swap (finance) (hist | edit) [13,976 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Swap''' is a derivative contract in which two parties agree to exchange specified cash flows according to predetermined terms over a specified period. The cash flows are generally calculated by reference to an underlying variable such as an interest rate, currency exchange rate, commodity price, or other financial reference. Swaps are commonly used for hedging, risk management, financing, and...")
- 12:2712:27, 20 August 2026 Derivative (finance) (hist | edit) [12,844 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Financial derivative''' is a financial contract whose value is derived from the value or performance of an underlying asset, financial instrument, index, rate, or other reference variable. Derivatives are commonly used for hedging, speculation, arbitrage, portfolio management, and risk transfer. The underlying reference can include equities, bonds, commodities, currencies, interest rates, credit instr...")
- 12:2512:25, 20 August 2026 Hedging (hist | edit) [15,006 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Hedging''' is a risk-management strategy in which an investor, business, or other market participant takes a position intended to offset or reduce the potential adverse effect of an existing exposure. Hedging is commonly used to manage risks arising from changes in asset prices, interest rates, exchange rates, commodity prices, credit conditions, and other financial variables. A hedge generally reduces exposure to a particular risk rather than eliminating all inv...")
- 03:5103:51, 20 August 2026 Option (finance) (hist | edit) [11,341 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Options''' are derivative contracts that give the holder the right, but not the obligation, to buy or sell an underlying asset at a specified price within a specified period or on a specified date. The specified price is called the strike price or exercise price. The buyer of an option generally pays the seller, or writer, a premium for this right. Options are widely used for Hedging...")
- 03:4803:48, 20 August 2026 Texas hedge (hist | edit) [11,074 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Texas hedge''' is an investment strategy in which an investor takes an offsetting position in a related security or financial instrument to reduce exposure to an existing position. The term is commonly used in financial markets and risk management. Unlike a conventional hedge that is designed primarily to reduce risk, a Texas hedge generally involves taking a position that can increase the potential for both gains and los...") originally created as "Texas Hedge"
17 August 2026
- 10:1210:12, 17 August 2026 Quantitative finance (hist | edit) [9,875 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Quantitative finance''' is a field of financial economics that applies mathematics, statistics, probability theory, and computer science to the analysis, valuation, trading, and risk management of financial assets and portfolios. It is also known as '''mathematical finance''' or '''financial engineering''' in contexts where mathematical and computational methods are...")
- 10:1010:10, 17 August 2026 Factor model (hist | edit) [7,760 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Factor model''' is a mathematical model used in financial economics, asset pricing, portfolio management, and quantitative finance to describe the relationship between an asset's return and one or more common factors. Factor models seek to explain differences in asset returns through systematic factors while separating those effects from asset-specific components. ==Gener...")
- 10:0910:09, 17 August 2026 Factor investing (hist | edit) [10,486 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Factor investing''' is an investment approach that involves selecting and weighting securities according to specific characteristics, known as factors, that are associated with differences in expected returns, risk, or other investment outcomes. Factor investing can be implemented across asset classes and is commonly used in portfolio management, quantitative investing, and...")
- 10:0810:08, 17 August 2026 Arbitrage pricing theory (hist | edit) [7,695 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Arbitrage pricing theory''' ('''APT''') is a multifactor asset-pricing theory that explains the expected return of an asset as a function of its sensitivity to multiple systematic risk factors. It was developed by Stephen Ross and introduced in 1976. Unlike the Capital asset pricing model (CAPM), which uses a single systematic risk factor represented by market beta, APT allows multiple economic and financial factors to influence expected...")
- 10:0710:07, 17 August 2026 Asset pricing (hist | edit) [10,670 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Asset pricing''' is a field of Financial economics that studies how the prices and expected returns of financial assets are determined. It examines the relationship between an asset's expected cash flows, risk, uncertainty, investor preferences, and market conditions. Asset-pricing theory is used to analyze securities and financial claims such as stocks, bonds, derivatives, and other investment assets. ==Basic conc...")
- 10:0110:01, 17 August 2026 Financial economics (hist | edit) [10,053 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Financial economics''' is a branch of economics that studies how financial markets, financial institutions, assets, and economic decisions interact. It applies economic theory and quantitative methods to questions involving the allocation of capital, valuation of financial assets, risk, investment, interest rates, and financial decision-making. Financial economics is closely related to finance, Financial econometrics|financial economet...")
- 09:5909:59, 17 August 2026 Risk premium (hist | edit) [6,642 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Risk premium''' is the additional return that investors require or expect for holding an investment that carries risk compared with a relatively risk-free investment. It is a fundamental concept in financial economics, asset pricing, portfolio management, and corporate finance. The risk premium compensates investors for bearing different types of investment risk, depending on...")
- 09:5809:58, 17 August 2026 Beta (finance) (hist | edit) [8,886 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Beta (finance)''' ('''β''') is a measure of an asset's or portfolio's sensitivity to movements in the return of a market benchmark. It is commonly used as a measure of systematic risk in the Capital asset pricing model (CAPM), portfolio management, and risk-adjusted performance analysis. A beta of 1 indicates that an asset has the same systematic risk as the market benchmark. A beta greate...")
- 09:5709:57, 17 August 2026 Jensen's alpha (hist | edit) [6,306 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Jensen's alpha''' is a risk-adjusted return measure that evaluates the performance of an investment or portfolio relative to the return predicted by the Capital asset pricing model (CAPM). It measures the excess or shortfall of an investment's actual return relative to its CAPM-implied expected return, given its level of systematic risk. ==Calculation== Jensen's alpha is commonly calculated as: <math> \alpha_p = R_p - \left[ R_f + \...")
- 09:5709:57, 17 August 2026 Treynor ratio (hist | edit) [5,034 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Treynor ratio''' is a risk-adjusted return measure that evaluates the excess return generated by an investment relative to its systematic risk. Unlike the Sharpe ratio, which uses total volatility as its measure of risk, the Treynor ratio uses beta to measure sensitivity to systematic market risk. ==Calculation== The Treynor ratio is commonly calculated as: <math> \text{Treynor Ratio} = \frac{R...")
- 09:5609:56, 17 August 2026 Sortino ratio (hist | edit) [4,666 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Sortino ratio''' is a risk-adjusted return measure that evaluates the return of an investment relative to its downside risk. Unlike the Sharpe ratio, which uses total volatility, the Sortino ratio focuses on returns below a specified target or minimum acceptable return. ==Calculation== The Sortino ratio is commonly calculated as: <math> \text{Sortino Ratio} = \frac{R_p-R_t} {\sigma_d} </math> where: * <math>R_p</math> = portfolio...")
- 09:5509:55, 17 August 2026 Capital asset pricing model (hist | edit) [7,869 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Capital asset pricing model''' ('''CAPM''') is a model in financial economics that describes the relationship between the expected return of an asset and its systematic risk. It is commonly used in asset pricing, portfolio management, corporate finance, and the estimation of the cost of equity. The model states that the expected return o...")
- 09:5409:54, 17 August 2026 Risk-adjusted return (hist | edit) [6,817 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Risk-adjusted return''' is a measure of investment performance that evaluates the return generated by an investment relative to the amount or type of risk undertaken to achieve that return. It allows investors to compare investments with different levels of risk rather than considering returns alone. A simplified representation is: <math> \text{Risk-Adjusted Return} = \frac{\text{Investment Return}} {\text{Measure of Risk}} </math> The appropriate measure of ri...")
- 09:5409:54, 17 August 2026 Risk-free rate (hist | edit) [6,831 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Risk-free rate''' is the theoretical rate of return on an investment that is assumed to have no risk of financial loss over a specified period. It is commonly used as a reference rate in financial economics, portfolio management, asset pricing, and risk-adjusted performance measurement. In practice, a truly risk-free investment does not exist. Financial analysts therefore...")
- 09:5309:53, 17 August 2026 Sharpe ratio (hist | edit) [6,204 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Sharpe ratio''' is a risk-adjusted return measure that evaluates the excess return generated by an investment relative to the risk-free rate in relation to the volatility of the investment's returns. It was developed by William F. Sharpe. The Sharpe ratio is commonly used to compare the risk-adjusted performance of investment portfolios, funds, and securities. ==Calculation== The Sharpe ratio is commonly calculate...")
- 09:5009:50, 17 August 2026 Information ratio (hist | edit) [6,068 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Information ratio''' ('''IR''') is a measure of the risk-adjusted performance of an investment portfolio relative to its benchmark. It compares the average active return generated by a portfolio with the variability of those active returns, commonly measured by tracking error. ==Calculation== The information ratio is commonly calculated as: <math> \text{Information Ratio} = \frac{\text{Average Active...")
- 09:4909:49, 17 August 2026 Active return (hist | edit) [4,581 bytes] WikiSysopIG (talk | contribs) (Created page with "'''Active return''' is the difference between the return of an investment portfolio and the return of its benchmark over a specified period. It measures whether a portfolio has outperformed or underperformed its benchmark. ==Calculation== Active return is calculated as: <math> \text{Active Return} = \text{Portfolio Return} - \text{Benchmark Return} </math> or, for period <math>t</math>: <math> A_t = R_{p,t} - R_{b,t} </math> where: * <m...")