We consider abstract non-negative self-adjoint operators on $L^2(X)$ which
satisfy the finite speed propagation property for the corresponding wave
equation. For such operators we introduce a restriction type condition which in
the case of the standard Laplace operator is equivalent to $(p,2)$ restriction
estimate of Stein and Tomas. Next we show that in the considered abstract
setting our restriction type condition implies sharp spectral multipliers and
endpoint estimates for the Bochner-Riesz summability.
Let $L$ be a non-negative self adjoint operator acting on $L^2(X)$ where $X$
is a space of homogeneous type. Assume that $L$ generates a holomorphic
semigroup $e^{-tL}$ whose kernels $p_t(x,y)$ have Gaussian upper bounds but
possess no regularity in variables $x$ and $y$. In this article, we study
weighted $L^p$-norm inequalities for spectral multipliers of $L$. We show sharp
weighted H\"ormander-type spectral multiplier theorems follow from Gaussian
heat kernel bounds and appropriate $L^2$ estimates of the kernels of the
spectral multipliers.