Spectral pollution and how to avoid it

Spectral Pollution and How to Avoid It (With Applications to Dirac and Periodic Schrödinger Operators)

This paper, devoted to the study of spectral pollution, contains both abstract results and applications to some self-adjoint operators with a gap in their essential spectrum occuring in Quantum Mechanics. First we consider Galerkin basis which respect the decomposition of the ambient Hilbert space into a direct sum H = PH⊕ (1 − P )H, given by a fixed orthogonal projector P , and we localize the...

How to avoid knowing it

Beliefs have been formally modelled in the last decades using doxastic logics. The possible worlds model and its associated Kripke semantics provide an intuitive semantics for these logics, but they seem to commit us to model agents that are logically omniscient (they believe every classical tautology) and perfect reasoners (their beliefs are closed under classical deductive closure). Thus, thi...

Incompatibility in Prescriptions and How to Avoid It

The Garbage Catastrophe of Aging and How to Avoid It

The Myth of the MAPE . . . and how to avoid it

Demand planners in supply chain organizations are accustomed to using the Mean Absolute Percentage Error (MAPE) as their best answer to measuring forecast accuracy. It is so ubiquitous that it is hardly questioned. I do not even find a consensus on the definition of the underlying forecast error among supply chain practitioners participating in the demand forecasting workshops I conduct worldwide.