Let
G=(V,E) be a finite graph. For
we denote by
the subgraph of
G that is induced by
v's neighbor set. We say that
G is
(a,b)-regular for
integers, if
G is
a-regular and
is
b-regular for every
. Recent advances in PCP theory call for the construction of infinitely many
(a,b)-regular expander graphs
G that are expanders also locally. Namely, all the graphs
should be expanders as well. While random regular graphs are expanders with high probability, they almost surely fail to expand locally. Here we construct two families of
(a,b)-regular graphs that expand both locally and globally. We also analyze the possible local and global spectral gaps of
(a,b)-regular graphs. In addition, we examine our constructions vis-a-vis properties which are considered characteristic of high-dimensional expanders.