The phrase "assumed to be simple" is correct and usable in written English.
It can be used when discussing something that is generally regarded as uncomplicated or straightforward, often in a theoretical or analytical context.
Example: "In many cases, the problem is assumed to be simple, but further analysis reveals its complexities."
Alternatives: "considered to be straightforward" or "regarded as uncomplicated."
But it has already been shown that some smaller animals, such as frogs and crickets, pick up information from the seismic part of what everybody had assumed to be simple acoustic (ie, airborne) signals.
The dynamic systems were considered basic and one-dimensional; the impedances were assumed to be uniform over the spatial extents of the dynamic systems and the propagation mode in each dynamic system was assumed to be simple and defined by a single speed.
Molecular graphs are assumed to be simple, undirected graphs.
The convex function is assumed to be "simple" in the sense that finding its proximal-like point is relatively easy.
In the early days of artificial intelligence research, "thinking" was assumed to be simple matter of connecting symbols together using discrete rules.
Φ is assumed to be simple (no two points occupy the same location) and stationary in space, i.e., its statistical properties do not change if Φ is shifted.
The validation sample is assumed to be a simple random subsample from the primary one.
The capillary radius variation was assumed to be a simple linear function and applied in the capillary model.
"Violence" is assumed to be one simple thing which produces specific and predictable results and not a theme which gets dealt with in many different ways.
The erosion rate is assumed to be a simple linear function of the basal velocity and therefore erosion only occurs where the bed is not frozen and basal sliding is possible.
While the pulse is assumed to be a simple boxcar with a given fixed energy and the baud length is the only design parameter, the results extend to many traditional ways of pulse compression coding through arguments derived from recent results on rigorous experiment comparison and perfect coding.
