The dependency is kactivities/frameworks branch which does not depend on nepomuk-core nor soprano.

Deps for kactivities are:

-- The following OPTIONAL packages have been found:

 * KDBusAddons

 * KWindowSystem

 * KCoreAddons

 * KConfig

-- The following REQUIRED packages have been found:

 * ECM (required version >= 0.0.8)

 * Qt5Sql

 * KF5

 * Qt5Test

 * Qt5Core

 * Qt5DBus

 * Qt5

Cheers,

Ivan