What is the test for determining whether a trial court has jurisdiction to sentence a defendant to prison?

Generally, a trial court is deprived of jurisdiction "once execution of the sentence has commenced." (People v. Karaman (1992) 4 Cal.4th 335, 344 (Karaman).) "In a criminal case, the execution of a judgment of conviction is the process of carrying the judgment into effect. [Citation.] The manner of executing a judgment sentencing a defendant to imprisonment is prescribed by the Penal Code. When a judgment other than death has been pronounced, and the judgment is for incarceration in a state prison, either a certified copy of the minute order or a certified abstract of the judgment 'shall be forthwith furnished to the officer whose duty it is to execute the . . . judgment, and no other warrant or authority is necessary to justify or require its execution'; the certified abstract or minute order constitutes the commitment. [Citations.] The commitment document is the order remanding the defendant to prison and is ' "the process and authority for carrying the judgment and sentence into effect." ' " (Ibid., fns. omitted.) "[T]he trial court's jurisdiction terminates either at the point the judgment is entered in the minutes of the court or at the time a defendant begins to serve his or her sentence, essentially whichever occurs first . . . ." (Id. at pp. 345-346.)