1/*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements.  See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License.  You may obtain a copy of the License at
8 *
9 *      http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17package org.apache.commons.math;
18
19/**
20 * Interface representing a <a href="http://mathworld.wolfram.com/Field.html">field</a>.
21 * <p>
22 * Classes implementing this interface will often be singletons.
23 * </p>
24 * @param <T> the type of the field elements
25 * @see FieldElement
26 * @version $Revision: 811685 $ $Date: 2009-09-05 19:36:48 +0200 (sam. 05 sept. 2009) $
27 * @since 2.0
28 */
29public interface Field<T> {
30
31    /** Get the additive identity of the field.
32     * <p>
33     * The additive identity is the element e<sub>0</sub> of the field such that
34     * for all elements a of the field, the equalities a + e<sub>0</sub> =
35     * e<sub>0</sub> + a = a hold.
36     * </p>
37     * @return additive identity of the field
38     */
39    T getZero();
40
41    /** Get the multiplicative identity of the field.
42     * <p>
43     * The multiplicative identity is the element e<sub>1</sub> of the field such that
44     * for all elements a of the field, the equalities a &times; e<sub>1</sub> =
45     * e<sub>1</sub> &times; a = a hold.
46     * </p>
47     * @return multiplicative identity of the field
48     */
49    T getOne();
50
51}
52