on subdifferential in hadamard spaces
چکیده
in this paper, we deal with the subdi erential concept onhadamard spaces. flat hadamard spaces are characterized, and nec-essary and sucient conditions are presented to prove that the subdif-ferential set in hadamard spaces is nonempty. proximal subdi erentialin hadamard spaces is addressed and some basic properties are high-lighted. finally, a density theorem for subdi erential set is established.