Concerns are interests important to the stakeholders in a system. They are used to identify and classify the system's stakeholders and to guide the selection of viewpoints for the architecture description. Reference: The TOGAF Standard | The Open Group Website, Section 3.2.1 Architecture Viewpoints

Gap analysis is a technique that is used to validate an architecture by highlighting the shortfall between the Baseline Architecture and the Target Architecture. One of the purposes of gap analysis is to identify missing functions that are either deliberately omitted, accidentally left out, or not yet defined in the Target Architecture. Missing functions are marked as gaps that need to be filled by developing or procuring the building blocks.

1E: To identify delivery vehicles (projects programs portfolios) that will deliver the Target Architecture 2F: To confirm readiness and ability to undergo change 3E: To determine whether an incremental approach is required and if so identify Transition Architectures that will deliver continuous business value 4G: To perform appropriate governance functions while the solution is being implemented

An Architecture Contract is a deliverable that specifies the responsibilities and obligations of the parties involved in the implementation and governance of an architecture. It ensures a system of continuous monitoring to check integrity changes decision-making and audit of all architecture-related activities. Reference: The TOGAF Standard | The Open Group Website, Section 3.3.4 Architecture Contracts.