  We define a reduction mechanism for LP and SDP formulations that degrades
approximation factors in a controlled fashion. Our reduction mechanism is a
minor restriction of classical reductions establishing inapproximability in the
context of PCP theorems. As a consequence we establish strong linear
programming inapproximability (for LPs with a polynomial number of constraints)
for many problems. In particular we obtain a $3/2-\varepsilon$
inapproximability for VertexCover answering an open question in
[arXiv:1309.0563] and we answer a weak version of our sparse graph conjecture
posed in [arXiv:1311.4001] showing an inapproximability factor of
$1/2+\varepsilon$ for bounded degree IndependentSet. In the case of SDPs, we
obtain inapproximability results for these problems relative to the
SDP-inapproximability of MaxCUT. Moreover, using our reduction framework we are
able to reproduce various results for CSPs from [arXiv:1309.0563] via simple
reductions from Max-2-XOR.
