The phrase "approximation to the spectrum" is correct and usable in written English.
It can be used in contexts related to mathematics, physics, or any field where one is discussing estimates or representations of a spectrum.
Example: "The approximation to the spectrum allows us to analyze the data more effectively without requiring exact values."
Alternatives: "estimate of the spectrum" or "representation of the spectrum".
One kind of color sequence that is often used by scientists is an approximation to the spectrum of light.
We conclude by proposing a solution to the general problem of approximating the spectrum of an arbitrary bounded operator by introducing the n-pseudospectrum and argue how that can be used as an approximation to the spectrum.
We show that a plot of −tdV/dt is an approximation to the spectrum of relaxation times that characterize the decay of V as a combination of exponential decays, and show how well such a plot can resolve different time constants.
In these cases it is easy and natural to compute the eigenvalues of large n × n submatrices of the infinite operator matrix, and to hope that if n is large enough then the resulting distribution of eigenvalues will give a good approximation to the spectrum of A. Numerical analysts call this the Galerkin method.
These asymptotically small perturbations are precisely those that result from modifying the initial-data by using formal approximations to the spectrum of the associated spectral problem; such modified data has always been a standard part of the analysis of zero-dispersion limits of integrable systems.
By incorporating the fundamentals of Floquet theory, an almost uniform approximation to the entire spectrum of the maximal extension is obtained, as opposed to an approximation of a few selected elements.
The logarithm of k1, λ, k2 and of the mean squared error of the approximation to the real spectrum are used as features.
The factor involving r π = m2 π is the spectrum weighted kinematic factor for the decay π → μ + v and γ ≈ 1.7 is the integral spectral index in a power-law approximation to the primary cosmic ray spectrum.
Thus, Sun et al.[16] employ a quadratic approximation to the range function in its deduction of the spectrum to design an imaging method.
DOSY spectra are calculated using an approximation to the inverse Laplace transform from a series of pulsed-field gradient NMR spectra acquired using gradient pulses with varying amplitudes.
An interpretation model based on an ellipsoidal approximation to the modified Mie theory (MMT) has been found appropriate to extract the information from measured MWT spectra of RBCs [ 8, 13].
