A Zero Test for Exp Log Constants Daniel Richardson Computer Science, Bath University, U.K. The Exp Log constants are the smallest collection of expressions which contains the rational numbers and is closed under addition, subtraction, multiplication, division, ExP, Log, and radicals. These expressions represent real or complex numbers, with some ambiguity because of the presence of notations for multivalued functions. The Zero problem for these constants is to decide whether or not the value of an expression E is actually zero, given E and a partial evaluation which is sufficient to remove ambiguitity about the value. A zero test is stated which attempts to solve this problem. The test is correct in that whenever it terminates it gives the correct value. If the Schanuel conjecture is true, the test will always eventually terminate. So the test is complete if the Schanuel conjecture is true. The algebraic machinery needed for the test is the ability to decide whether or not an algebraic function of several variables, given in terms of field operations and radicals, is identically zero.