Display screen or portion thereof with a graphical user interface

[0001]FIG. 1 is a front view of a display screen or portion thereof with a graphical user interface showing a first image in a sequence, according to our new design;

[0002]FIG. 2 is a second image in the sequence thereof;

[0003]FIG. 3 is a third image showing portions of the sequence thereof;

[0004]FIG. 4 is perspective view of a handheld device showing the first image;

[0005]FIG. 5 is a perspective view thereof showing the second image; and,

[0006]FIG. 6 is a perspective view thereof showing the third image.

[0007]The outermost broken lines in FIGS. 1-3 showing a display screen or portion thereof, and broken lines within showing elements of the graphical user interface illustrate portions of the article that form no part of the claimed design. The additional broken line in FIGS. 4-6 showing an electronic device illustrate environmental subject matter and form no part of the claimed design. The appearance of any portion of the graphical user interface between the break lines illustrated in FIGS. 3 and 6 forms no part of the claimed design.