Physical world and mathematics

Fiducial inference

Fiducial inference is a statistical inference framework that produces a probability distribution for an unknown parameter without a prior, proposed by R. A. Fisher in 1930.

Fiedler vector

A Fiedler vector is an eigenvector of a graph's Laplacian matrix corresponding to the second smallest eigenvalue, known as the algebraic connectivity, and is central to spectral graph partitioning.

Field (mathematics)

In mathematics, a field is a set equipped with addition and multiplication satisfying the usual laws of arithmetic; the rational, real, and complex numbers are the familiar examples.

Field (physics)

In physics, a field, also called a physical field, is a quantity with a value at every point in space, mediating forces like gravity and electromagnetism.

Field capacity

Field capacity is the water content retained in soil after saturation, once excess water has drained under gravity; introduced in 1931, it remains standard in irrigation and hydrologic modeling.

Field electron emission

Field electron emission, also called cold emission or field emission, is the release of electrons from a solid into vacuum by quantum tunneling under a strong electric field.

Field evaporation

Field evaporation is the removal of atoms from a solid surface as positive ions under an intense electric field of a few volts per nanometer.

Field experiment

A field experiment is a study that randomly assigns an intervention to people, schools, or firms in real-world settings, so outcome differences reveal causal effects.

Field extension

A field extension is a pair of fields L/K where K is a subfield of L, the central object of Galois theory and its measure of size, the degree.

Field ion microscopy

Field ion microscopy (FIM) images individual atoms on a needle-shaped specimen tip by ionizing an imaging gas, invented by Erwin W. Müller at Pennsylvania State University in 1951.

Field ionization

Field ionization is the removal of an electron from an atom or molecule by a strong electric field, requiring about 10⁷ to 10⁸ V/cm and underpinning field-ionization mass spectrometry.

A field notebook is a bound, portable record book in which a scientist, most often a field geologist, records observations, measurements, sketches, and interpretations at outcrops, serving as geology's primary scientific record.

Field of fractions

The field of fractions of an integral domain is the smallest field containing it, built as the rationals are built from the integers; also called the quotient field.

Field of sets

A field of sets, also called an algebra of sets, is a collection of subsets of a set closed under finite union, intersection, and complementation.

Field of view

Field of view (FOV), sometimes called angle of acceptance, is the extent of the scene an optical system records, in cameras, microscopes, telescopes, and the human eye.

Field research

Field research, also called field work, is research conducted in natural, real-world settings rather than in laboratories, spanning ethnographic participant observation, field experiments, and scientific field campaigns.

Field spectroscopy

Field spectroscopy is the measurement of spectral reflectance of natural surfaces in the field using portable spectroradiometers, chiefly to support calibration and validation of satellite and airborne imagery.

Field-emission scanning electron microscopy

Field-emission scanning electron microscopy (FE-SEM), also known as FESEM, is a form of scanning electron microscopy using a field-emission gun, applied in materials science, nanotechnology, and biology.

Field-failure and early-life failure analysis

Field-failure and early-life failure analysis is the statistical study of how products fail in actual use, drawing on warranty claims, returns, and service records to forecast failures and costs.