X chromosomes
and randomness in females, 1014

X-ray crystallography, 993

X-ray diffraction patterns, 1082

Xerographic printing, 1195

XML
and computer communication, 1182

Xor (⊻)
axioms for, 803
calculus of expressions, 1170
confluence of, 1037
DNF representation of, 1096
emulated by rule 30, 703
lower bounds on in DNF, 1143
size of formula for, 1096
table for, 806
words in languages for, 1173

Xor rules
see also Additive cellular automata
see also Rule 90