A note on properties of condition numbers

Clovis C. Gonzaga, Hugo J. Lara

The condition numbers described by Stewart, Todd and others for a matrix $ A $ are given by the suprema of the norms of all the oblique projection operators respectively on the image space of $ A^T $ and the null space of $ A $. This paper shows that these two numbers coincide.

Department of Mathematics, Federal University of Santa Catarina, Cx. Postal 5210, 88040-970 Florianopolis, SC, Brazil