Display Screen or Portion Thereof with a Graphical User Interface

FIG. 1 is a front view of a display screen or portion thereof with a graphical user interface; and,

FIG. 2 is a front enlarged view of a portion of FIG. 1 (denoted in that figure with reference number 2 ).

The dash-dot broken lines show the display screen or portion thereof and form no part of the claimed design. The dash-dash broken lines in the figures denote portions of the display screen or portion thereof with a graphical user interface that form no part of the claimed design. The dash-dash broken rectangular line indicated by the number “ 2 ” in FIG. 1 indicates a portion of FIG. 1 that is enlarged in FIG. 2 and forms no part of the claimed design. The wavy broken lines in the figures denote unclaimed boundaries of the display screen or portion thereof with a graphical user interface and form no part of the claimed design. The appearance of any portion of the display screen or portion thereof with a graphical user interface between the wavy broken lines forms no part of the claimed design.

The ornamental design for a display screen or portion thereof with a graphical user interface, as shown in the figures, may be within a graphical user interface of a computing system, such as a computing system utilized for robotic surgery.