\alefsymThe \alefsym command in LaTeX is used to represent the aleph symbol, which is the first letter of the Hebrew alphabet. In mathematics, it is often used to denote the cardinality of infinite sets, particularly in set theory.
Aleph-null, the smallest infinite cardinality
\alefsym_0The next larger cardinality after aleph-null
\alefsym_1An infinite cardinality larger than all finite alephs
\alefsym_\omega