\subsetneqqThe symbol \subsetneqq is used in mathematics to denote a subset that is not equal to the set it is compared with. It indicates that one set is a proper subset of another, meaning all elements of the first set are in the second set, but the second set contains additional elements not found in the first.
Set A is a proper subset of set B, meaning A is contained within B but is not equal to B.
A \subsetneqq BThe set containing elements 1 and 2 is a proper subset of the set containing elements 1, 2, and 3.
\{1, 2\} \subsetneqq \{1, 2, 3\}Set X is a proper subset of set Y, indicating that all elements of X are in Y, but Y has more elements than X.
X \subsetneqq Y