← All parts of this equation

Equation 1 · Part 3 · Seventy-Five Thousand Generations of E. coli, and Counting

Symbol a

wceiling(t)=1+a t1+b tw_{\text{ceiling}}(t) = 1 + \frac{a\,t}{1 + b\,t}
aa

What this part means

a occurs above the fraction bar. The numerator is divided by the entire denominator below it.

Its job in the formula

a occurs above the fraction bar. The numerator is divided by the entire denominator below it.

The passage around this formula

Against that record, Wiser, Ribeck and Lenski fit fitness trajectories from all twelve populations across 50,000 generations against two competing functional shapes for how relative fitness might grow with time. One is a form that saturates — fitness rising quickly at first and then flattening toward a fixed asymptote, the kind of ceiling a “diminishing returns” reading of Lenski’s 1991 result would predict. The other is a power-law form, with no fixed limit: growth continues indefinitely, at an ever-slowing rate…

Read this part in the article →

Learn the underlying idea

A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

Open the illustrated variables: a letter stands for a value guide →

See this notation across published equations →

Sources cited in the article section

These citations provide research context; check each source for the exact claim it supports.