Recursion

Sum

Naturally, nothing begins;

yet, one exists:
integral integer,
infinite set.

x = x:                                                           a reflex;
if x = y, then y = x:                                symmetric;
if x = y and y = z, then x = z:             in transit.

All are equal:
injection in progression,
n + 1.

No successor is nothing—
zero undone.

*[ WSB ].