In topology, a subbase (or subbasis, prebase, prebasis) for a topological space X {\displaystyle X} with topology τ {\displaystyle \tau } is a subcollection...

In highway engineering, subbase is the layer of aggregate material laid on the subgrade, on which the base course layer is located. It may be omitted...

course, and subbase course constructed over a compacted, natural soil subgrade. When building a three layer flexible pavement, the subbase layer is not...

ultrafilter. A filter subbase that is ultra is necessarily a prefilter. A filter subbase is ultra if and only if it is a maximal filter subbase with respect to...

The pavement and subbase thicknesses are designed to withstand the wheel loads. Sometimes, geogrids are used to reinforce the subbase and further strengthen...

stabilized. If the final pavement is to have vehicle traffic, a layer of subbase of crushed stone or concrete must come next—this layer will even out the...

It is also called formation level. The subgrade provides support to the subbase level and acts as an integral load-bearing layer. Failure of the subgrade...

open sets Neighbourhood (mathematics) – Open set containing a given point Subbase – Collection of subsets that generate a topology Tubular neighborhood –...

used to define topologies. A weaker notion related to bases is that of a subbase for a topology. Bases for topologies are also closely related to neighborhood...

and filter subbases, all of which appear naturally and repeatedly throughout topology. Examples include neighborhood filters/bases/subbases and uniformities...