Size-Depth Tradeo s for Algebraic Formulae

Size-Depth Tradeoffs for Algebraic Formulae

Shape Effects and Definition of Hydraulic Radius in Manning 's Equation in Open Channel Flow

In the Manning equation the hydraulic radius can be defined as the cross-section dimension of the shape. In pipe flow the bed shear stress is assumed to be uniformly distributed along the wetted perimeter which cannot be true in open channel flow. Hence, three approximation of the true boundary shear-stress distribution are examined and more practical conveyance depth or resistance radius formu...

Depth-3 Arithmetic Formulae over Fields of Characteristic Zero

In this paper we prove quadratic lower bounds for depth-3 arithmetic circuits over fields of characteristic zero. Such bounds are obtained for the elementary symmetric functions, the (trace of) iterated matrix multiplication, and the determinant. As corollaries we get the first nontrivial lower bounds for computing polynomials of constant degree, and a gap between the power of depth-3 arithmeti...

Valiant’s Polynomial-Size Monotone Formula for Majority

The existence of polynomial-size (monotone) formulae is known to be equivalent to the existence of logarithmic-depth (monotone) circuits of bounded fan-in. Anyhow, we shall prove the existence of logarithmic-depth monotone formulae (of bounded fan-in) for majority. Actually, two radically different proofs are known: The first proof uses a rather complicated construction of sorting networks of l...

Types of Depth and Formula Size

We use a rank-based measure on rational expressions in indeterminates over a field and define notions of size and depth with associated subparts of formulae for expressions. Formulae are allowed to have as inputs expressions from a large set rather than just constants and indeterminates. A general lower bound is derived and this is used to deduce an exponential lower bound, subject to depth ass...