plural of fencepost problem

plural of problem space

plural of scientific problem

The need to make a decision between alternatives that are both desirable.

A kind of puzzle in which there is one common factor in a first set of diagrams that is missing from a second set. The solver (possibly a computer program) must identify this factor.

(quantum mechanics) The unresolved problem of what causes a wavefunction to collapse into an eigenstate, or whether wavefunctions collapse at all.

The situation where a spam filter or search engine blocks or modifies content because the text contains a string of letters shared with an obscene word.

(mathematics) The challenge of proving that the only solution of the Diophantine equation :∑ₙ₌₁ᴺn²=M²; with N > 1 is when N = 24 and M = 70.

plural of decision problem

(computing theory) A question in some formal system with a yes-or-no answer, depending on the values of input parameters.