  Douglas Walton's multitudinous contributions to the study of argumentation
seldom, if ever, directly engage with argumentation in mathematics.
Nonetheless, several of the innovations with which he is most closely
associated lend themselves to improving our understanding of mathematical
arguments. I concentrate on two such innovations: dialogue types ({\S}1) and
argumentation schemes ({\S}2). I argue that both devices are much more
applicable to mathematical reasoning than may be commonly supposed.
