assuming that ...; supposing that ...
Used to introduce a hypothetical condition or premise, often in logical or explanatory contexts. Follows a clause in plain form.
彼が来ると仮定して、準備を進めよう。
Let's proceed with preparations, assuming that he will come.
この理論が正しいと仮定して、次のステップを考えます。
Assuming this theory is correct, we will consider the next step.
Combination of the case particle と (quoting/marking a condition) and the te-form of the verb 仮定する (to assume).