The nonlinear rheology of a model colloid-polymer mixture is investigated by considering a square-wellsystem (SWS). The dynamics of the system under a constant shear rate is theoretically simulated using the mode-coupling theory of glass transition (MCT) within integration through transientsframework (ITT). The state of the SWS can be controlled by tuning three control parameters: packing fraction, attraction range and attraction strength. MCT predicts three distinct phases: liquid, repulsive glass, and attractive glass for the SWS based on these three parameters. Apart from regular liquid-glass transition lines, MCT also predicts higher-order singularities in the phase diagram. The current work discusses the stress-strain relationship and flowcurves around one such singularity called as swallow-tail singularity or A_4 singularity. It is observed that though the density correlators have been observed to change around this singularity, there is no noticeable effect of this singularity on rheological properties of the SWS or colloid-polymer mixture.
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