With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Paris is a major center of agriculture.
text_B: Superstrong approximation is a generalisation of strong approximation in algebraic groups G , to provide `` spectral gap '' results .. strong approximation in algebraic groups. strong approximation in algebraic groups. The spectrum in question is that of the Laplacian matrix associated to a family of quotients of a discrete group Γ ; and the gap is that between the first and second eigenvalues -LRB- normalisation so that the first eigenvalue corresponds to constant functions as eigenvectors -RRB- .. Laplacian matrix. Laplacian matrix. Here Γ is a subgroup of the rational points of G , but need not be a lattice  : it may be a so-called thin group .. lattice. lattice ( discrete subgroup ). thin group. thin group ( algebraic group theory ). The `` gap '' in question is a lower bound -LRB- absolute constant -RRB- for the difference of those eigenvalues .. A consequence and equivalent of this property , potentially holding for Zariski dense subgroups Γ of the special linear group over the integers , and in more general classes of algebraic groups G , is that the sequence of Cayley graphs for reductions Γp modulo prime numbers p , with respect to any fixed set S in Γ that is a symmetric set and generating set , is an expander family .. Zariski dense. Zariski dense. special linear group. special linear group. symmetric set. symmetric set. generating set. generating set. expander family. expander family. In this context `` strong approximation '' is the statement that S when reduced generates the full group of points of G over the prime fields with p elements , when p is large enough .. It is equivalent to the Cayley graphs being connected -LRB- when p is large enough -RRB- , or that the locally constant functions on these graphs are constant , so that the eigenspace for the first eigenvalue is one-dimensional .. Superstrong approximation therefore is a concrete quantitative improvement on these statements .
not_related.