underlie

To lie in a position directly beneath something.

To lie under or beneath.

A stratum of clay underlies the surface gravel.

To serve as a basis of; form the foundation of.

a doctrine underlying a theory

[…] she was carved into the bole of a red cedar tree. Sun and storm had bleached the wood, moss here and there softened the crudeness of the modelling; sincerity underlay every stroke.

To be subject to; be liable to answer, as a charge or challenge.

The knight of Ivanhoe […] underlies the challenge of Brian der Bois Guilbert.

To underlay.