bilinear functional; bilinear form; Sobolev spaces; local bilinear functional; boundary-value problems for elliptic differential operators
The scalar product of the FEM basis functions with non-intersecting supports vanishes. This property is generalized and the concept of local bilinear functional in a Hilbert space is introduced. The general form of such functionals in the spaces $L_2(a,b)$ and $H^1(a,b)$ is given.
 V. Jarník: Differential Calculus. Publishing House of the Czech. Acad. Sci., Prague, 1953. (In Czech.)