First-order filters are considered by many audiophiles to be ideal for crossovers.

First-order linear non-homogeneous ODEs ( ordinary differential equations ) are not separable.

First-order logic is a formal system used in mathematics, philosophy, linguistics, and computer science.

First-order logic is distinguished from propositional logic by its use of quantified variables.

First-order logic also satisfies several metalogical theorems that make it amenable to analysis in proof theory, such as the Löwenheim – Skolem theorem and the compactness theorem.

First-order logic is of great importance to the foundations of mathematics, because it is the standard formal logic for axiomatic systems.

First-order logic allows reasoning about properties that are shared by many objects, through the use of variables.

First-order logic can also express predicates with more than one parameter.

First-order predicate calculus is commonly used as a mathematical basis for these systems, to avoid excessive complexity.

First-order logic requires at least one additional rule of inference in order to obtain completeness.

* Stanford Encyclopedia of Philosophy: First-order Model Theory – by Wilfrid Hodges.

First-order phase transitions exhibit a discontinuity in the first derivative of the free energy with respect to some thermodynamic variable.

First-order phase transitions are those that involve a latent heat.

See First-order logic.

First-order control is contrasted to higher-order control.

:: First-order solution: increase police presence and introduce stricter laws against trafficking in drugs.

First-order predicate logic uses rules of inference to deal with logical quantifiers.

First-order logic uses only variables that range over individuals ( elements of the domain of discourse ); second-order logic has these variables as well as additional variables that range over sets of individuals.

First-order approximation ( also 1st order ) is the term scientists use for a further educated guess at an answer.

First-order arithmetic satisfies these preconditions, but the theorem applies to much more general formal systems.

First-order governance is the level at which problems are identified and solutions enacted.

First-order indexicality can be defined as the first level of pragmatic meaning that is drawn from an utterance.

* Hodges, Wilfrid, " First-order Model Theory ", The Stanford Encyclopedia of Philosophy ( Summer 2005 Edition ), Edward N. Zalta ( ed.

Many content filters have an option which allows authorized people to bypass the content filter.

These generalizations of the convolution have applications in the field of numerical analysis and numerical linear algebra, and in the design and implementation of finite impulse response filters in signal processing.

Cloth filters or sari filtration, though very basic, have significantly reduced the occurrence of cholera when used in poor villages in Bangladesh that rely on untreated surface water.

" Significant amounts " of hexavalent chromium were found in the water of more than 40 homes in the area, some of which have now been fitted with state-monitored filters on their water supply.

FIR filters can be made to have zero phase, but with IIR filters that is generally impossible.

All low-pass second-order continuous-time filters have a transfer function given by

Some have one or two filters attached to the face piece ; others have a large filter connected to the face piece by a hose.

Many scare stories have originated from various Russian gas masks and their filters that are now common in surplus stores ; the GP-5 was often considered to have an asbestos filter, however like most cold-war masks it only contains activated charcoal.

Differential interference contrast requires a polarized light source to function ; two polarizing filters have to be fitted in the light path, one below the condenser ( the polarizer ), and the other above the objective ( the analyzer ).

The stem needs a long channel of constant position and diameter running through it, although filter pipes have varying diameters and can be successfully smoked even without filters or adapters.

Special purpose hydrogen-alpha narrow bandpass filters as well as aluminum coated glass attenuation filters ( which have the appearance of mirrors due to their extremely high optical density ) on the front of a telescope provide safe observation through the eyepiece.

The IF filter originally involved a complex collection of tuneable inductors that needed careful adjustment to reconstruct the rest of the vestigial sideband, but since the 1970s or early 1980s these have been replaced with precision electromechanical surface acoustic wave ( SAW ) filters.

Most sextants also have filters for use when viewing the sun and reducing the effects of haze.

Much of the chapter responds to George Jackson Mivart's criticisms, including his claim that features such as baleen filters in whales, flatfish with both eyes on one side and the camouflage of stick insects could not have evolved through natural selection because intermediate stages would not have been adaptive.

Analog filters consist of imperfect electronic components, whose values are specified to a limit tolerance ( e. g. resistor values often have a tolerance of +/- 5 %) and which may also change with temperature and drift with time.

Analog filters do not have the same capability, because finite impulse response filters require delay elements.

Protective respirators and masks should have particle filters, particularly for aquatinting.

The inserted filters may have varying densities, with correspondingly varied percentages of transmission, that subtractively mix colors.

Either IIR or FIR filters may be used, however FIR have the advantage that transients are suppressed if the fractional delay is changed over time.