School of Mathematics,

University of the Witwatersrand,

P Bag 3 Wits,

2050 Johannesburg,

SOUTH AFRICA

E-mail: kara@maths.wits.ac.za

**Symmetries, conservation laws and "partial" Lagrangians**

**Abstract:**

We show how one can construct conservation laws of Euler-Lagrange-type
equations via Noether-type symmetries associated with partial Lagrangians.
This is

particularly of significance when a differential equation is not derivable
from a variational priciple, for e.g., scalar evolution equations.