Z _________________________________________________________________________________________________

zag number

PL alternating permutation .

zero

Denoted 0. (1) As placeholder in basal notation (PL), e.g., decimal; thus, 5207 is thereby distinguished from 527

. (2)As initator of counting (a.k.a. natural) number system (PL) by recursion (PL). Originated in arithmetic of India by at least 650 AD. Disseminated by Islamic mathematication, hence, "Hindu-Arabic notation" (PL).

zig number

PL alternating permutation .

zigzag number, Euler's

PL alternating permutation.