AMA Manual of Style - Stacy L. Christiansen, Cheryl Iverson 2020

Punctuation
Mathematical Composition

Punctuation after a set-off equation is helpful and often clarifies the meaning. Display equations are often preceded by punctuation.

In the linear quadratic equation model, the survival probability for cells receiving a j increment of radiation, D_j, is as follows:

where α and β are the variables of the linear quadratic equation model.

Do not use periods after a set-off equation if the equation is preceded by a period.