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# degree(MultirationalMap) -- degree of a multi-rational map

- Function: degree
- Usage:
    `degree Phi`
- Inputs:
  - Phi, a multi-rational map
- Outputs:
  - an integer, the degree of Phi. So this value is 1 if and only if the map is birational onto its image.

## Description

This is just a shortcut for (last multidegree Phi)/(degree image Phi).

    i1 : ZZ/300007[x_0..x_3], f = rationalMap {x_2^2-x_1*x_3, x_1*x_2-x_0*x_3, x_1^2-x_0*x_2}, g = rationalMap {x_1^2-x_0*x_2, x_0*x_3, x_1*x_3, x_2*x_3, x_3^2};

    i2 : Phi = last graph rationalMap {f,g};

    o2 : MultirationalMap (rational map from threefold in PP^3 x PP^2 x PP^4 to PP^2 x PP^4)

    i3 : time degree Phi
     -- used 0.541689s (cpu); 0.401056s (thread); 0s (gc)

    o3 = 1

## See also

- degree(MultirationalMap,Option) -- degree of a multi-rational map using a probabilistic approach
- degree(RationalMap) -- degree of a rational map
- multidegree(MultirationalMap) -- projective degrees of a multi-rational map
- degreeMap(RationalMap) -- degree of a rational map

## Ways to use this method:

- degree(MultirationalMap) -- degree of a multi-rational map

The source of this document is in /build/macaulay2-88fgJW/macaulay2-1.25.11+ds/M2/Macaulay2/packages/MultiprojectiveVarieties.m2:3253:0.