Symbol w
w is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Read this term in its guide →Published equation contexts
Why this formula appears here
The reason is an ordering constraint. Under the standard assumption that a population moves by fixing one beneficial mutation at a time, a mutational path is accessible only if fitness increases at every single step: . A single step that violates this inequality closes the entire path, regardless of how high the endpoint is. Sign epistasis is exactly the mechanism that produces such steps, and reciprocal sign epistasis — where each of two mutations is deleterious without the other and beneficial with it — is what creates genuinely separated local optima.
Read the representative guide
Symbol g_0
is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Read this term in its guide →Symbol g_1
is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Read this term in its guide →Symbol g_L
is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Read this term in its guide →How to interpret it
Read this expression with the definitions, units, and assumptions supplied by the article.
Research cited beside this formula
Published contexts (1)
A symbol can carry a different meaning in another article. Each occurrence keeps its own guide and term definitions.
Equation 2 · Evolution & Ecology
Fitness Landscapes and the Limits of the Metaphor
This equation states a bound: one expression must stay on the indicated side of the other under the article’s assumptions.
The reason is an ordering constraint. Under the standard assumption that a population moves by fixing one beneficial mutation at a time, a mutational path is accessible only if fitness increases at every single step: . A single step that violates this inequality closes the entire path, regardless of how high the endpoint is. Sign epistasis is exactly the mechanism that produces such steps, and reciprocal sign epistasis — where each of two mutations is deleterious without the other and beneficial with it — is what creates genuinely separated local optima.
Equation guide → · Article →